Protein adhesives containing an anhydride, carboxylic acid, and/or carboxylate salt compound and their use

ABSTRACT

The invention provides protein adhesives, and methods of making and using such adhesives. The protein adhesives contain a protein-bonding agent and plant protein composition, such as an isolated water-soluble protein fraction or ground plant meal obtained from plant biomass. The protein-bonding agent can be an anhydride compound, carboxylic acid compound, carboxylate salt compound, or combinations thereof. The protein adhesives are useful in bonding together lignocellulosic materials and other types of materials.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the national stage of International (PCT) PatentApplication Serial No. PCT/IB2013/002188, filed Jul. 30, 2013, whichclaims the benefit of and priority to U.S. Provisional PatentApplication Ser. No. 61/677,399, filed Jul. 30, 2012, the contents ofeach of which are hereby incorporated by reference for all purposes.

FIELD OF THE INVENTION

The invention relates to protein adhesives, and to methods of making andusing such adhesives. The protein adhesives contain a protein-bondingagent and a plant protein composition, such as isolated water-solubleprotein fraction or ground plant meal obtained from plant biomass. Theprotein-bonding agent can be an anhydride compound, carboxylic acidcompound, carboxylate salt compound, or combinations thereof. Theprotein adhesives are useful in bonding together lignocellulosicmaterials and other types of materials.

BACKGROUND

Adhesive compositions are used extensively in the labeling, packaging,and wood products industries. Adhesives are used in the labelingindustry to bond a label to a substrate, such as a bottle, package orenvelope. Adhesives are used in the packing industry to bond togethercomponents to form a package, such as a paper envelope or a cardboardbox. Adhesives are used in the wood products industry to make compositessuch as chipboard, fiberboard, and related composite wood products.Recent environmental concerns emphasize the need for adhesivecompositions that are environmentally friendly. In particular, the needexists for adhesive compositions that reduce the need for petroleumfeedstock, minimize use of toxic chemicals, and are amenable to the cureconditions and performance requirements for use in the labeling,packaging, and wood products industries.

In response to the need for environmentally friendly adhesivecompositions, there has been renewed interest in using certain soyproducts to form adhesive compositions. However, there are multiplechallenges in developing an adhesive composition from soy products. Forexample, the adhesive composition when cured to form a binder must havesufficient bond strength. Another challenge is that the adhesivecomposition must have sufficient pot life so that it does not curebefore being applied to a substrate to be bound to the adhesive. It isalso important that the soy product be capable of production on largescale at economically feasible terms, and that it is amenable to cureconditions used in the labeling, packaging, and wood productsindustries.

The present invention addresses these needs and provides other relatedadvantages.

SUMMARY OF THE INVENTION

The invention provides protein adhesive compositions, methods of makingand using such adhesives, and articles prepared using such adhesives.The protein adhesive compositions contain a protein-bonding agent and aplant protein composition, such as isolated water-soluble proteinfraction or ground plant meal obtained from plant biomass. Theprotein-bonding agent can be an anhydride compound, carboxylic acidcompound, carboxylate salt compound, or combination thereof. The plantprotein composition is advantageous because it is prepared from plantbiomass, a renewable feedstock that is generally a waste by-product ofthe agricultural industry. The adhesive compositions are useful inbonding together lignocellulosic materials, as well as other types ofmaterials. One preferred aspect of the invention provides transparent,pressure-sensitive adhesives, which contain isolated water-solubleprotein fraction, an anhydride compound, and a plasticizer. Anotherpreferred aspect of the invention provides transparent,pressure-sensitive adhesives, which contain isolated water-solubleprotein fraction, a carboxylic acid compound or a carboxylate saltcompound, and optionally a plasticizer. These transparent,pressure-sensitive adhesives are contemplated to be particularly usefulfor sealing envelopes, adhering labels to lignocellulosic materials, andotherwise bonding together lignocellulosic materials.

Accordingly, one aspect of the invention provides an adhesivecomposition comprising: (a) an isolated water-soluble protein fraction;and (b) at least 0.1% (w/w) of a protein-bonding agent selected from thegroup consisting of an anhydride compound, carboxylic acid compound,carboxylate salt compound, and combinations thereof. The adhesivecomposition may further comprise water to produce a liquid adhesivecomposition that is particularly useful in bonding togetherlignocellulosic materials. One advantage of using isolated water-solubleprotein fraction as the protein component is that upon curing theadhesive composition provides a solid binder composition that istransparent. Another desirable feature of the solid binder compositionis that it exhibits adhesive tack at ambient temperature. Adhesive tackat ambient temperature permits the solid binder composition to functionas a pressure-sensitive adhesive, whereby an article can be bonded tothe solid binder composition simply by temporarily applying pressure toforce the article into contact with the pressure-sensitive adhesive. Thedegree of adhesive tack can be manipulated by adding a plasticizer, suchas glycerin, to the adhesive composition. It is appreciated that use ofa plasticizer is optional, and the amount of plasticizer included in thecomposition is selected in order to achieve the desired amount of tackfor the end application.

Another aspect of the invention provides an adhesive compositioncomprising: (a) ground plant meal; and (b) at least 0.1% (w/w) of aprotein-bonding agent selected from the group consisting of an anhydridecompound, carboxylic acid compound, carboxylate salt compound, andcombinations thereof. The adhesive composition may further comprisewater to produce a liquid adhesive composition that is particularlyuseful in bonding together lignocellulosic materials. It is desirablethat upon curing the adhesive composition provide a solid bindercomposition with sufficient adhesive tack at ambient temperature to bondtogether lignocellulosic materials. The degree of adhesive tack can bemanipulated by adding a plasticizer, such as glycerin, to the adhesivecomposition.

Another aspect of the invention provides a solid binder compositionformed by curing an adhesive composition described herein.

Another aspect of the invention provides a method of bonding a firstarticle to a second article. The method comprises the steps of (a)depositing on a surface of the first article any one of the foregoingadhesive compositions thereby to create a binding area; and (b)contacting the binding surface with a surface of the second articlethereby to bond the first article to the second article. The methodoptionally also comprises the step of, after step (b), permitting theadhesive composition to cure, which can be facilitated by theapplication of pressure, heat or both pressure and heat.

Another aspect of the invention provides a method of producing acomposite material. The method comprises the steps of (a) combining afirst article and a second article with any one of the foregoingadhesive compositions to produce a mixture; and (b) curing the mixtureproduced by step (a) to produce the composite material. The curing cancomprise applying pressure, heat or both pressure and heat to themixture.

In certain embodiments, the first article, the second article or boththe first and second articles are lignocellulosic materials, orcomposite materials containing lignocellulosic material. The firstarticle, the second article or both the first and second articles cancomprise a metal, a resin, a ceramic, a polymer, a glass or acombination thereof. The first article, the second article, or both thefirst article and the second article can be a composite. In addition,the invention provides an article produced by each of the foregoingmethods of manufacture.

Another aspect of the invention provides an article comprising (i) asubstrate and (ii) a pressure-sensitive adhesive formed by curing anadhesive composition on the substrate. In certain embodiments, thesubstrate is a lignocellulosic substrate, such as paper or cardboard.

Another aspect of the invention provides an article comprising two ormore components bonded together using one or more of the adhesivecompositions described herein. The bonded components can be selectedfrom the group consisting of paper, wood, glass, metal, fiberglass, woodfiber, ceramic, ceramic powder, plastic (for example, a thermosetplastic), and a combination thereof. In certain other embodiments, thebonded components can be selected from the group consisting of paper,wood, glass, metal, fiberglass, wood fiber, ceramic, ceramic powder,sand, plastic (for example, a thermoset plastic), and a combinationthereof. The invention provides an article (for example, a compositematerial, laminate, or a laminate containing composite material)produced using one or more of the adhesive compositions describedherein.

Depending upon the adhesive used, the solid binder composition formed bycuring the adhesive composition may be transparent and/or have a certaindegree of adhesive tack at ambient temperature. Also, an article formedby bonding substrates together using the adhesive composition can becharacterized according to the strength of the bond between thesubstrates. For example, when the article contains lignocellulosicmaterial in the composite material or laminate, the article may becharacterized by exhibiting no less than 50%, or optionally no less than75%, cohesive failure of the lignocellulosic component when the articleis placed under a loading stress sufficient to break the article. Incertain embodiments, the article exhibits no less than 50% cohesivefailure of the lignocellulosic component when the article is placedunder a loading stress sufficient to break the article.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will become apparent from the following description ofpreferred embodiments, as illustrated in the accompanying drawings.Like-referenced elements identify common features in the correspondingdrawings. The drawings are not necessarily to scale, with emphasisinstead being placed on illustrating the principles of the presentinvention, in which:

FIG. 1 is a flow chart showing the steps of an exemplary method forproducing isolated polypeptide compositions useful in the practice ofthe invention;

FIG. 2 shows overlaid solid state FTIR spectra for water-soluble andwater-insoluble protein fractions isolated from digested castor lot5-90;

FIG. 3 shows solid state FTIR spectra of isolated water-soluble andwater-insoluble fractions from digested castor, where the carbonyl amideregion is expanded;

FIG. 4 shows solid state FTIR spectra of isolated water-soluble andwater-insoluble fractions from digested castor where the N—H stretchingregion is expanded;

FIG. 5 shows overlaid solid state FTIR spectra of isolated fractionsfrom castor protein (lot 5-94), showing an expansion of the carbonylamide region (water-soluble fraction, andwater-insoluble/water-dispersible fraction);

FIG. 6 shows the solid state FTIR spectra of isolated water-soluble andwater-insoluble fractions from castor protein (lot 5-94), where the N—Hand O—H stretch regions are expanded;

FIG. 7 shows overlaid solid state FTIR spectra of the isolatedwater-insoluble/water-dispersible fractions from castor protein (lot5-94) and from enzyme digested castor (lot 5-90);

FIG. 8 shows overlaid solid state FTIR spectra of isolated water-solubleand water-insoluble fractions from digested soy, where the carbonylamide region is expanded, where the spectra were vertically scaled toachieve equivalent absorbance intensities for the amide-I carbonylstretch;

FIG. 9 shows overlaid solid state FTIR spectra of isolated water-solubleand water-insoluble fractions from digested soy, where the N—Hstretching region is expanded;

FIG. 10 shows overlaid solid state FTIR spectra of isolatedwater-soluble polypeptide fractions from digested soy and digestedcastor;

FIG. 11 shows overlaid solid state FTIR spectra of isolatedwater-insoluble fractions from digested soy and soy flour;

FIG. 12 shows overlaid solid state FTIR surface ATR spectra of theisolated water-insoluble/water-dispersible fractions from multipleprotein samples (digested soy lot 5-81, soy flour, castor proteinisolate lot 5-94, digested castor lot 5-90) where the carbonyl amideregion is expanded;

FIG. 13 is a two-dimensional HSQC ¹H-¹⁵N NMR spectrum for digestedcastor (lot 5-83) in d6-DMSO, showing two regions of interest denotedRegion A and Region B;

FIG. 14 is a two-dimensional HSQC ¹H-¹⁵N NMR spectrum forwater-insoluble/water-dispersible polypeptide fraction derived fromdigested castor (lot 5-83) in d6-DMSO, again showing Region A and RegionB;

FIG. 15 is a two-dimensional HSQC ¹H-¹⁵N NMR spectrum, where Region Afrom FIG. 14 has been magnified;

FIG. 16 shows solid state FTIR spectra of isolated water-soluble andwater-insoluble fractions obtained from ground soy meal, where the N—Hand O—H stretch regions are expanded;

FIG. 17 shows overlaid solid state FTIR spectra of isolatedwater-soluble and water-insoluble fractions obtained from ground soymeal, where the carbonyl amide region is expanded and the spectra werevertically scaled to achieve equivalent absorbance intensities for theamide-I carbonyl stretch;

FIG. 18 shows overlaid solid state FTIR spectra of isolatedwater-soluble and water-insoluble/water-dispersible protein fractionsobtained from ground canola meal, where the N—H and O—H stretch regionsare expanded, as described further in Example 5;

FIG. 19 shows overlaid solid state FTIR spectra of isolatedwater-soluble and water-insoluble/water-dispersible protein fractionsobtained from ground canola meal, where the carbonyl amide region isexpanded and the spectra were vertically scaled to achieve equivalentabsorbance intensities for the amide-I carbonyl stretch, as describedfurther in Example 5;

FIG. 20 shows overlaid solid state FTIR spectra of isolatedwater-soluble and water-insoluble/water-dispersible protein fractionsobtained from soy flour, as described further in Example 5;

FIG. 21 shows overlaid solid state FTIR spectra of isolatedwater-insoluble/water-dispersible protein fractions obtained from soymeal and soy flour, as described further in Example 5;

FIG. 22 is a solid state FTIR spectra of PMEMA-mixed acid/anhydride(PMEMA-Acid), overlaid with PMEMA-Na Salt, and the subtraction spectrarepresenting the 1/1 WS/PMEMA-mixed acid/anhydride product (Sample A),and the 1/1 WS/PMEMA-Na salt product (Sample B), as described in Example6; and

FIG. 23 depicts paper coupons containing the phrase “BLEED TEST” in ink,where the coupons have been pressed by hand onto pre-dried,adhesive-coated glass slides (where the left-most recitation of “BLEEDTEST” on each coupon was printed using black ink, the middle recitationof “BLEED TEST” on each coupon was printed using red ink, and theright-most recitation of “BLEED TEST” on each coupon was printed usingblue ink), as described in Example 12.

DETAILED DESCRIPTION

The invention provides protein adhesive compositions, methods of makingand using such adhesives, and articles prepared using such adhesives.The protein adhesive compositions contain a protein-bonding agent and aplant protein composition, such as isolated water-soluble proteinfraction or ground plant meal obtained from plant biomass. Theprotein-bonding agent can be an anhydride compound, carboxylic acidcompound, carboxylate salt compound, or combination thereof. The plantprotein composition is advantageous because it is prepared from plantbiomass, a renewable feedstock that is generally a waste by-product ofthe agricultural industry. The adhesive compositions are useful inbonding together lignocellulosic materials, as well as other types ofmaterials. One preferred aspect of the invention provides transparent,pressure-sensitive adhesives, which contain isolated water-solubleprotein fraction, an anhydride compound, and a plasticizer. Thesetransparent, pressure-sensitive adhesives are contemplated to beparticularly useful for sealing envelopes, adhering a label tolignocellulosic materials, and otherwise bonding togetherlignocellulosic materials.

The following sections describe the protein adhesive compositions,materials that may be included in the protein adhesive compositions,methods of making and using such adhesives, and articles formed fromsuch adhesives. Features described in one section are not to be limitedto any particular section, but may be combined with features in anothersection.

I. Protein Adhesive Compositions

One aspect of the invention provides an adhesive composition comprisinga plant protein composition and a protein-bonding agent. The plantprotein composition may be a isolated water-soluble protein fraction,ground plant meal, or isolated water-insoluble/water-dispersible proteinfraction, each of which are described in more detail in Section IIbelow. Exemplary adhesive compositions are described in more detailbelow.

Part A: Adhesive Compositions Containing Isolated Water-Soluble ProteinFraction

One aspect of the invention provides an adhesive composition comprising:(a) an isolated water-soluble protein fraction; and (b) at least 0.1%(w/w) of a protein-bonding agent selected from the group consisting ofan anhydride compound, carboxylic acid compound, carboxylate saltcompound, and combinations thereof. Adhesive compositions containingisolated water-soluble protein fraction as the protein component canprovide an advantage in that upon curing they form a solid bindercomposition that is transparent.

Physical properties of the adhesive composition can be adjusted byaltering the relative amount of (a) isolated water-soluble proteinfraction and (b) protein-bonding agent used in the adhesive composition.For example, in certain embodiments, the ratio of (i) the weight percentof isolated water-soluble protein fraction in the adhesive compositionto (ii) the weight percent of protein-bonding agent in the adhesivecomposition is from about 25:1 to about 1:4, about 20:1 to about 1:1,about 15:1 to about 1:1, or about 10:1 to about 1:1. In certain otherembodiments, the ratio of (i) the weight percent of isolatedwater-soluble protein fraction in the adhesive composition to (ii) theweight percent of protein-bonding agent in the adhesive composition isfrom about 10:1 to about 2:1. In certain other embodiments, the ratio of(i) the weight percent of isolated water-soluble protein fraction in theadhesive composition to (ii) the weight percent of protein-bonding agentin the adhesive composition is from about 5:1 to about 1:1, or fromabout 4:1 to about 2:1.

In certain other embodiments, the ratio of (i) the weight percent ofisolated water-soluble protein fraction in the adhesive composition to(ii) the weight percent of protein-bonding agent in the adhesivecomposition is from about 20:1 to about 1:20. In certain otherembodiments, the ratio of (i) the weight percent of isolatedwater-soluble protein fraction in the adhesive composition to (ii) theweight percent of protein-bonding agent in the adhesive composition isfrom about 10:1 to about 1:2. In certain other embodiments, the ratio of(i) the weight percent of isolated water-soluble protein fraction in theadhesive composition to (ii) the weight percent of protein-bonding agentin the adhesive composition is from about 8:1 to about 1:1.

In certain other embodiments, the protein-bonding agent is an anhydridecompound and the ratio of (i) the weight percent of isolatedwater-soluble protein fraction in the adhesive composition to (ii) theweight percent of anhydride compound in the adhesive composition is fromabout 20:1 to about 1:1. In certain other embodiments, the ratio of (i)the weight percent of isolated water-soluble protein fraction in theadhesive composition to (ii) the weight percent of anhydride compound inthe adhesive composition is from about 10:1 to about 2:1. In certainother embodiments, the ratio of (i) the weight percent of isolatedwater-soluble protein fraction in the adhesive composition to (ii) theweight percent of anhydride compound in the adhesive composition is fromabout 5:1 to about 1:1, or from about 4:1 to about 2:1.

In addition, physical properties of the adhesive composition can beadjusted by altering the overall amount of isolated water-solubleprotein fraction in the adhesive composition. For example, in certainembodiments, the adhesive composition comprises from about 1% (w/w) toabout 95% (w/w) isolated water-soluble protein fraction, from about 1%(w/w) to about 90% (w/w) isolated water-soluble protein fraction, fromabout 5% (w/w) to about 90% (w/w) isolated water-soluble proteinfraction, from about 10% (w/w) to about 80% (w/w) isolated water-solubleprotein fraction, or from about 15% (w/w) to about 50% (w/w) isolatedwater-soluble protein fraction. In certain other embodiments, theadhesive composition comprises from about 1% (w/w) to about 65% (w/w)isolated water-soluble protein fraction. In certain other embodiments,the adhesive composition comprises from about 5% (w/w) to about 80%(w/w) isolated water-soluble protein fraction. In certain otherembodiments, the adhesive composition comprises from about 5% (w/w) toabout 50% (w/w) isolated water-soluble protein fraction. In certainother embodiments, the adhesive composition comprises from about 1%(w/w) to about 10% (w/w) isolated water-soluble protein fraction. Incertain other embodiments, adhesive the composition comprises from about2% (w/w) to about 5% (w/w) isolated water-soluble protein fraction.

The isolated water-soluble protein fraction is described in more detailin Section II and may be characterized by one or more of the followingfeatures: (i) an amide-I absorption band between about 1633 cm⁻¹ and1680 cm⁻¹, as determined by solid state FTIR; (ii) an amide-II bandbetween approximately 1522 cm⁻¹ and 1560 cm⁻¹, as determined by solidstate FTIR; (iii) two prominent 1° amide N—H stretch absorption bandscentered at about 3200 cm⁻¹, and at about 3300 cm⁻¹, as determined bysolid state FTIR; (iv) a prominent cluster of protonated nitrogen nucleidefined by ¹⁵N chemical shift boundaries at about 94 ppm and at about100 ppm, and ¹H chemical shift boundaries at about 7.6 ppm and at about8.1 ppm, as determined by solution state, two-dimensionalproton-nitrogen coupled NMR; (v) an average molecular weight of betweenabout 600 and about 2,500 Daltons; or (vi) an inability to stabilize anoil-in-water emulsion, wherein, when an aqueous solution comprising 14parts by weight of protein dissolved or dispersed in 86 parts by weightof water is admixed with 14 parts by weight of PMDI, the aqueoussolution and the PMDI produce an unstable suspension thatmacroscopically phase separates under static conditions within fiveminutes after mixing.

In certain embodiments, the isolated water-soluble protein fraction isderived from corn, wheat, sunflower, cotton, rapeseed, canola, castor,soy, camelina, flax, jatropha, mallow, peanuts, algae, sugarcanebegasse, tobacco, whey, or a combination thereof.

The adhesive composition may optionally further comprise isolatedwater-insoluble/water-dispersible protein fraction. The isolatedwater-insoluble/water-dispersible protein fraction is described indetail in Section II and may be characterized by one or more of thefollowing features: (a) an amide-I absorption band between about 1620cm⁻¹ and 1632 cm⁻¹ and an amide-II band between approximately 1514 cm⁻¹and 1521 cm⁻¹, as determined by solid state Fourier Transform InfraredSpectroscopy (FTIR), (b) a prominent 2° amide N—H stretch absorptionband centered at about 3272 cm⁻¹, as determined by solid state FTIR, (c)an average molecular weight of between about 600 and about 2,500Daltons, (d) two protonated nitrogen clusters defined by ¹⁵N chemicalshift boundaries at about 86.2 ppm and about 87.3 ppm, and ¹H chemicalshift boundaries at about 7.14 ppm and 7.29 ppm for the first cluster,and 1H chemical shift boundaries at about 6.66 ppm and 6.81 ppm for thesecond cluster, as determined by solution state, two-dimensionalproton-nitrogen coupled NMR, and (e) is capable of dispersing anoil-in-water or water-in-oil to produce a homogeneous emulsion that isstable for least 5 minutes.

One benefit of including a quantity (e.g., from about 0.1% (w/w) about5% (w/w) of the adhesive composition) of isolatedwater-insoluble/water-dispersible protein fraction in the adhesivecomposition is that it may make the adhesive composition more amenablefor use with a hydrophobic plasticizer. Exemplary hydrophobicplasticizers include oil-based plasticizers, such as linseed oil, soyoil, castor oil, and derivatives of each of the foregoing, such as anester (e.g., an alkyl ester) of any of the foregoing oils.

Part B: Adhesive Compositions Containing Ground Plant Meal

Another aspect of the invention provides an adhesive compositioncomprising: (a) ground plant meal; and (b) at least 0.1% (w/w) of aprotein-bonding agent selected from the group consisting of an anhydridecompound, carboxylic acid compound, carboxylate salt compound, andcombinations thereof. Adhesive compositions containing ground plant mealas the protein component provide advantages in that ground plant meal isreadily available at minimal cost from commercial sources and is arenewal feedstock.

Physical properties of the adhesive composition can be adjusted byaltering the relative amount of (a) ground plant meal and (b)protein-bonding agent used in the adhesive composition. For example, incertain embodiments, the adhesive composition comprises from about 1%(w/w) to about 25% (w/w) ground plant meal. In certain otherembodiments, the adhesive composition comprises from about 2% (w/w) toabout 10% (w/w) ground plant meal. In certain other embodiments, thecomposition comprises from about 2% (w/w) to about 5% (w/w) ground plantmeal. In certain embodiments, the ratio of (i) the weight percent ofground plant meal in the adhesive composition to (ii) the weight percentof protein-bonding agent in the adhesive composition is from about 10:1to about 1:1. In certain embodiments, the ratio of (i) the weightpercent of ground plant meal in the adhesive composition to (ii) theweight percent of protein-bonding agent in the adhesive composition isfrom about 5:1 to about 1:1.

In certain embodiments, the protein-bonding agent is an anhydridecompound and the ratio of (i) the weight percent of ground plant meal inthe adhesive composition to (ii) the weight percent of anhydridecompound in the adhesive composition is from about 25:1 to about 1:4,from about 15:1 to about 1:1, from about 10:1 to about 1:1, or fromabout 4:1 to about 2:1. In certain embodiments, the ratio of (i) theweight percent of ground plant meal in the adhesive composition to (ii)the weight percent of anhydride compound in the adhesive composition isfrom about 5:1 to about 1:1.

The adhesive composition may optionally further comprise isolatedwater-soluble protein fraction. Isolated water-soluble protein fractionis described in more detail in Section II.

Additionally, the adhesive composition may optionally further compriseisolated water-insoluble/water-dispersible protein fraction. Theisolated water-insoluble/water-dispersible protein fraction is describedin detail in Section II and may be characterized by one or more of thefollowing features: (a) an amide-I absorption band between about 1620cm⁻¹ and 1632 cm⁻¹ and an amide-II band between approximately 1514 cm⁻¹and 1521 cm⁻¹, as determined by solid state Fourier Transform InfraredSpectroscopy (FTIR), (b) a prominent 2° amide N—H stretch absorptionband centered at about 3272 cm⁻¹, as determined by solid state FTIR, (c)an average molecular weight of between about 600 and about 2,500Daltons, (d) two protonated nitrogen clusters defined by ¹⁵N chemicalshift boundaries at about 86.2 ppm and about 87.3 ppm, and ¹H chemicalshift boundaries at about 7.14 ppm and 7.29 ppm for the first cluster,and ¹H chemical shift boundaries at about 6.66 ppm and 6.81 ppm for thesecond cluster, as determined by solution state, two-dimensionalproton-nitrogen coupled NMR, and (e) is capable of dispersing anoil-in-water or water-in-oil to produce a homogeneous emulsion that isstable for least 5 minutes.

Part C: Adhesive Compositions Containing IsolatedWater-Insoluble/Water-Dispersible Protein Fraction

Another aspect of the invention provides an adhesive compositioncomprising: (a) an isolated water-insoluble/water-dispersible proteinfraction; and (b) at least 0.1% (w/w) of a protein-bonding agentselected from the group consisting of an anhydride compound, carboxylicacid compound, carboxylate salt compound, and combinations thereof. Theisolated water-insoluble/water-dispersible protein fraction is describedin more detail in Section II and may be derived from corn, wheat,sunflower, cotton, rapeseed, canola, castor, soy, camelina, flax,jatropha, mallow, peanuts, algae, sugarcane begasse, tobacco, whey, or acombination thereof.

In certain embodiments, the protein-bonding agent is an anhydridecompound.

II. Plant Protein Composition

The plant protein composition is derived from plant biomass and, assuch, provides the benefit that it is a renewable feedstock. The plantprotein composition may be isolated water-soluble protein fraction,isolated water-insoluble/water-dispersible protein fraction, or groundplant meal as described in more detail below.

A. Preparation of Isolated Water-Soluble Protein Fraction andPreparation of Isolated Water-Insoluble/Water-Dispersible ProteinFraction

The water-soluble protein fraction and thewater-insoluble/water-dispersible protein fraction can be obtained fromplant material using the Water Washing Method or the Acid PrecipitationMethod described below. The plant material used as starting material inthe Water Washing Method and the Acid Precipitation Method can be, forexample, corn, wheat, sunflower, cotton, rapeseed, canola, castor, soy,camelina, flax, jatropha, mallow, peanuts, algae, sugarcane bagasse,tobacco, or whey. In certain embodiments, the plant material used asstarting material in the Water Washing Method and the Acid PrecipitationMethod is plant meal or a protein isolate. The protein compositionobtained from the Water Washing Method and or Acid Precipitation Methodmay optionally be further modified by enzymatic digestion and/orchemical modification.

The terms “protein” and “polypeptide” are used synonymously and refer topolymers containing amino acids that are joined together, for example,via peptide bonds or other bonds, and may contain naturally occurringamino acids or modified amino acids. The polypeptides can be isolatedfrom natural sources or synthesized using standard chemistries. Thepolypeptides may be modified or derivatized by either natural processes,such as post-translational processing, or by chemical modificationtechniques well known in the art. Modifications or derivatizations mayoccur anywhere in the polypeptide, including, for example, the peptidebackbone, the amino acid side-chains and the amino or carboxyl termini.Modifications include, for example, cyclization, disulfide bondformation, demethylation, deamination, formation of covalentcross-links, formation of pyroglutamate, formylation,gamma-carboxylation, glycosylation, GPI anchor formation, hydroxylation,iodination, methylation, myristolyation, oxidation, pegylation,proteolytic digestion, phosphorylation, etc.

Water Washing Method

Water-insoluble/water-dispersible protein fraction can be isolated fromplant meal (e.g., castor meal, soy meal, or canola meal) by washing withwater to remove water-soluble proteins and water-soluble components. Theresidue left after the water wash is thewater-insoluble/water-dispersible protein fraction. The water-solubleprotein fraction can be isolated by concentrating aqueous extracts fromthe water washing. Plant meal used in the process can be ground toreduce particle size, which may, in certain instances, provideprocessing advantages.

Water-insoluble/water-dispersible protein fraction can also be isolatedfrom, for example, soy protein isolate or from soy flour. The procedureinvolves washing the soy protein isolate or soy flour with water toremove water-soluble proteins and water-soluble components from therespective soy protein isolate or the water-flour mixture.

The water-insoluble/water-dispersible protein fraction described abovemay be used directly as a wet slurry in an adhesive composition, or itmay be dried and optionally ground to form a particulate mixture.Similarly, the water-soluble protein fraction described above may beused directly as a wet slurry in an adhesive composition, or it may bedried and optionally ground to form a particulate mixture.

In certain embodiments, the pH of the water used to wash the plant mealis about 7. In certain other embodiments, the pH of the water used toperform one or more of the washes may be alkaline.

It is appreciated that the water-insoluble/water-dispersible proteinfraction obtained using the Water Washing Method may, in certaininstances, contain water-insoluble components in addition towater-insoluble protein. If the performance requirements of an adhesiverequire a water-insoluble/water-dispersible protein fraction having alarger amount of water-insoluble protein, then the Acid PrecipitationMethod can be used to prepare the water-insoluble/water-dispersibleprotein fraction.

Acid Precipitation Method

Water-insoluble/water-dispersible protein fraction comprising arelatively higher quantity of water-insoluble protein can be preparedusing the Acid Precipitation Method. The Acid Precipitation Method isshown schematically in FIG. 1. This method can also be used to obtainwater-soluble protein fraction.

As shown in FIG. 1, the starting material (for example, ground meal) isdispersed in alkaline, aqueous media at pH 6.5-13 for at least 5minutes, at least 20 minutes, at least 40 minutes or at least 1 hour, toform a mixture. Starting materials include, for example, canola meal,canola protein isolate, castor meal, castor protein isolate, soy meal,or soy protein isolate, or a combination thereof. Then, the pH of themixture is lowered by the addition of acid (to provide a mixture with apH in the range of, for example, 4.0-5.0) to precipitate both a portionof water-soluble proteins and water-insoluble proteins. Then, thewater-insoluble material (i.e., the precipitate) is harvested. Theharvested material is washed with water and the remainingwater-insoluble/water-dispersible material is harvested. The resultingwater-insoluble/water-dispersible material can be used as is or driedusing drying techniques known in the art.

Further, as shown in FIG. 1, the water-soluble proteins can be harvestedat a number of places. For example, water-soluble proteins can beharvested after the starting material is mixed in aqueous media, afterneutralization, and as a supernatant from the washing steps. Theresulting protein can be used as is or dried using drying techniquesknown in the art.

The water-insoluble/water-dispersible material produced according to themethod in FIG. 1 can disperse or emulsify oil in water or water in oil.The physical and chemical properties of thewater-soluble/water-dispersible fraction are described in more detailbelow. In addition, the physical and chemical properties of thewater-soluble protein fraction are described in more detail below.

Enzymatic Digestion/Chemical Hydrolysis

The Water Washing Method and Acid Precipitation Method can include oneor more enzyme digestion and/or chemical hydrolysis steps. Digestion canbe facilitated using one or more enzymes, and hydrolysis can befacilitated using one or more chemicals, for example, acid- oralkali-based hydrolysis. For example, in the Acid Precipitation Method,the starting material (for example, the ground meal) can be exposed toenzymatic digestion before or after, or both before and after theincubation of the starting material in the alkaline aqueous media.Alternatively, or in addition, an enzymatic digestion step can beperformed on the material following addition of acid to provide amixture with a pH in the range of 4.0 to 5.0. Alternatively, or inaddition, the harvested water-insoluble/water-dispersible material canbe exposed to enzymatic digestion prior to washing. Alternatively, or inaddition, the material harvested after washing can be exposed toenzymatic digestion. Chemical hydrolysis, however, can occur with orreplace the enzymatic digestion steps noted above.

It is understood that enzymes useful in the digestion of the proteinfractions include endo- or exo-protease of bacterial, fungal, animal orvegetable origin or a mixture of thereof. Useful enzymes include, forexample, a serine-, leucine-, lysine-, or arginine-specific protease.Exemplary enzymes include trypsin, chymotrypsins A, B and C, pepsin,rennin, microbial alkaline proteases, papain, ficin, bromelain,cathepsin B, collagenase, microbial neutral proteases, carboxypeptidasesA, B and C, camosinase, anserinase, V8 protease from Staphylococcusaureus and many more known in the art. Also combinations of theseproteases may be used.

Also commercially available enzyme preparations such as, for example,Alcalase®, Chymotrypsine 800s, Savinase®, Kannase®, Everlase®,Neutrase®, Flavourzyme® (all available from Novo Nordisk, Denmark),Protex 6.0L, Peptidase FP, Purafect®, Purastar OxAm®, Properase®(available from Genencor, USA), Corolase L10 (Rohm, Germany), Pepsin(Merck, Germany), papain, pancreatin, proleather N and Protease N(Amano, Japan), BLAP and BLAP variants available from Henkel, K-16-likeproteases available from KAO, or combinations thereof. Table 1 describesthe amino acid specificity of certain useful endonucleases.

TABLE 1 No. Amino Acid Notation Commercial Endopeptidase(s) 1 Alanine APronase ®; Neutrase ®: 2 Cysteine C Papain 3 Aspartic D Fromase ®; 4Glutamic E Alcalase ®; 5 Phenylalanine F Neutrase ®: Fromase ® 6 GlycineG Flavorzyme ®; Neutrase ®: 7 Histidine H Properase ®; 8 Isoleucine INeutrase ®: 9 Lysine K Alcalase ®; Trypsin; Properase ® 10 Leucine LAlcalase ®; Esperase ®; Neutrase ®: 11 Methionine M Alcalase ®;Neutrase ®: 12 Asparagine N Savinase ®; Flavourzyme ®; Duralase ®; 13Proline P Pronase ®; Neutrase ®: 14 Glutamine Q Alcalase ® 15 Arginine RTrypsin; Properase ®; 16 Serine S Savinase ®; Flavourzyme ®; Duralase ®;17 Threonine T Savinase ®; Flavourzyme ®; Duralase ®; 18 Valine VNeutrase ®: 19 Tryptophan W Neutrase ®: Fromase ® 20 Tyrosine YAlcalase ®; Esperase ®; Fromase ®

Depending upon the choice of enzyme(s), enzymatic digestion usually isconducted under aqueous conditions at the appropriate pH conditions (forexample, depending upon the enzyme or enzyme mixture at neutral or atlow pH). In certain digestion systems, the digestion optimally occurs ata pH less than 9, or less than 8. For certain applications the pH of theaqueous protein digestion system is in the range of 3-9, 4-8 or 5-7.5.

Once digestion has proceeded to the desired extent, the resultingproduct optionally is washed and used as is or dried to form a powder.The drying can be performed by techniques known in the art, includingspray drying, freeze drying, oven drying, vacuum drying, or exposure todesiccating salts (such as phosphorous pentoxide or lithium chloride).

Chemical Modification of Proteins

In certain embodiments, the proteins in the isolated protein fractionsare further derivatized. Suitable processes for derivatization of theprotein fractions are provided in the literature. The nature and extentof modification will depend in large part on the composition of thestarting material. The derivative can be produced by, for example,replacing at least a portion of primary amine groups of said isolatedprotein with hydroxyl groups, deaminating the protein, or replacing aportion of amide groups of the protein with carboxyl groups, etc. Inother embodiments, the isolated protein compositions described hereinare obtained by reacting the protein with protein modifying agents, forexample, nitrous oxide, nitrous acid, salts of nitrous acid, or acombination thereof.

B. Characterization of the Water-Insoluble/Water-Dispersible ProteinFraction

The water-insoluble/water-dispersible protein fraction can becharacterized accordingly to multiple physical properties. For example,the water-insoluble/water-dispersible protein fraction can becharacterized according to its capacity to disperse oil in water orwater in oil. The water-insoluble/water-dispersible protein fractionshould, at a minimum, disperse at least some oil in water or water inoil. The amount of oil that can be dispersed in water or the amount ofwater that can be dispersed in oil is a physical property thatcharacterizes a water-insoluble/water-dispersible protein fraction.

The water-insoluble/water-dispersible protein fraction can also becharacterized according to i) absorption band(s) observed by solid stateFTIR, ii) molecular weight range of the proteins in the fraction, andiii) features in a solution state, two-dimensional proton-nitrogencoupled NMR spectrum of the fraction.

Accordingly, in certain embodiments, thewater-insoluble/water-dispersible fraction is characterized by one ormore of the following features: (i) a prominent amide-I absorption bandbetween about 1620 cm⁻¹ and 1645 cm⁻¹, (ii) an amide-II band betweenapproximately 1514 cm⁻¹ and 1545 cm⁻¹, as determined by solid stateFTIR, and (iii) is capable of dispersing an oil-in-water or water-in-oilto produce a homogeneous emulsion that is stable for least 5 minutes.

In certain other embodiments, the water-insoluble/water-dispersiblefraction is characterized by one or more of the following features: (i)an amide-I absorption band between about 1620 cm⁻¹ and 1642 cm⁻¹ and anamide-II band between approximately 1514 cm⁻¹ and 1540 cm⁻¹, asdetermined by solid state FTIR, (ii) a prominent 2° amide N—H stretchabsorption band centered at about 3272 cm⁻¹, as determined by solidstate FTIR, and (iii) is capable of dispersing an oil-in-water orwater-in-oil to produce a homogeneous emulsion that is stable for least5 minutes.

In certain other embodiments, the water-insoluble/water-dispersiblefraction is characterized by one or more of the following features: (i)an amide-I absorption band between about 1620 cm⁻¹ and 1632 cm⁻¹ and anamide-II band between approximately 1514 cm⁻¹ and 1521 cm⁻¹, asdetermined by solid state FTIR, (ii) a prominent 2° amide N—H stretchabsorption band centered at about 3272 cm⁻¹, as determined by solidstate FTIR, (iii) an average molecular weight of between about 600 andabout 2,500 Daltons (determined using, for example, MALDI massspectrometry), (iv) two protonated nitrogen clusters defined by ¹⁵Nchemical shift boundaries at about 86.2 ppm and about 87.3 ppm, and ¹Hchemical shift boundaries at about 7.14 ppm and 7.29 ppm for the firstcluster, and ¹H chemical shift boundaries at about 6.66 ppm and 6.81 ppmfor the second cluster, as determined by solution state, two-dimensionalproton-nitrogen coupled NMR.

As described above, water-insoluble/water-dispersible fraction iscapable of suspending or emulsifying oil in water or water in oil toproduce a homogeneous suspension or emulsion stable, by visualinspection, for least 5 minutes. In certain embodiments, the dispersionor emulsion exhibits substantially no phase separation by visualinspection for at least 10, 15, 20, 25, or 30 minutes, or even 1, 2, 3,4, 5, 6, 9, 12, 18, or 24 hours after mixing the polypeptide compositionwith the oil. As shown in Example 4, thewater-insoluble/water-dispersible fraction is capable of emulsifying ordispersing a wide selection of oils, including, for example, an organicpolyisocyanate (for example, PMDI) mineral oil, soybean oil, derivatizedsoybean oil, motor oil, castor oil, derivatized castor oil, dibutylphthalate, epoxidized soybean oil, corn oil, vegetable oil, caprylictriglyceride, Eucalyptus oil, and tributyl o-acetylcitrate. In anexemplary assay, 14 parts (by weight) of a protein sample of interest ismixed with 86 parts (by weight) of water and the resulting solution ordispersion is mixed with 14 parts (by weight) of oil, for example, PMDI.Under these conditions, the water-insoluble/water-dispersible proteinfraction produces a dispersion or emulsion exhibits substantially nophase separation by visual inspection for at least 5 minutes aftermixing the polypeptide composition with the oil. The assay can beperformed with the other oils.

In certain other embodiments, the water-insoluble/water-dispersiblefraction is further characterized by its ability to emulsify ordisperse, in water, one or more of the following hydrophobic liquids andhydrophobic solids: a silicone (e.g., a silicone oil or a silicone gel),a fluorocarbon (e.g., a solid wax fluorocarbon or a liquid oilfluorocarbon), a fluorinated polyol, a wax (e.g., a solid carboxylicacid ester (e.g., an ester of stearic acid), a salt of a carboxylic acid(e.g., a salt of stearic acid, e.g., zinc stearate), a hydrocarbon wax,and a fluorinated hydrocarbon wax), a liquid carboxylic acid ester thatis hydrophobic, and a liquid hydrocarbon.

In yet other embodiments, the water-insoluble/water-dispersible fractionis further characterized by its ability to emulsify or disperse one ormore of the following agents in water: BE Square 165 Amber PetroleumMicrocrystalline Wax from Baker Hughes, Inc.; limonene; FluoroLink D-10Fluorinated polyol from Solvay Solexis, Inc; Tego Protect-5000functionalized silicone fluid from Evonik Tego Chemie GmbH; SoyLecithin; Castor Oil; Zinc Stearate; Dow Corning FS-1265 Fluid, 300 cST(Trifluoropropyl Methicone) from Dow Corning; and T-Sil-80, hydroxyterminated polydimethylsiloxane from Siovation, Inc.

In yet other embodiments, the water-insoluble/water-dispersible fractionis further characterized by its ability to emulsify or disperse anamalgam comprising a partially exfoliated clay in an oil carrier. In yetother embodiments, the water-insoluble/water-dispersible fraction isfurther characterized by its ability to emulsify or disperse a meltedwax in water. In certain embodiments, the dispersion or emulsionexhibits substantially no phase separation by visual inspection for atleast 10, 15, 20, 25, or 30 minutes, or even 1, 2, 3, 4, 5, 6, 9, 12,18, or 24 hours after mixing the polypeptide composition with the agent.

In certain embodiments, the water-insoluble/water-dispersible fractionis substantially free of primary amines, carboxylic acids, amine salts,and carboxylate salts.

The water-insoluble/water-dispersible protein fraction can act as asurfactant to an organic polyisocyanate (e.g., PMDI), loweringinterfacial tension to the point where the water insoluble organicpolyisocyante is readily emulsified with minimal energy input, creatingan oil-in-water or water-in-oil emulsion.

In certain embodiments, the polypeptide fractions used in thecompositions and methods provided herein, can have a weight averagemolecular weight of between about 500 and 25,000 Daltons. Usefulpolypeptide fractions can have a weight average molecular weight ofbetween about 500 and 2,500 Daltons, between about 700 and 2,300 Da.,between about 900 and 2,100 Da., between about 1,100 and 1,900 Da.,between about 1,300 and 1,700 Da., or between about 1,000 and 1,300 Da.,between about 2,000 and 2,500 Da., or between about 1,000 and 2,500 Da.

In certain embodiments, the water-insoluble/water-dispersible proteinfraction provides a stable emulsion, dispersion or suspension, forexample, an aqueous emulsion, dispersion or suspension, comprising fromabout 1% to about 90% (w/w) of an oil and from about 1% to about 99%(w/w) of an isolated polypeptide composition, wherein the isolatedpolypeptide composition produces a stable emulsion or dispersion of theoil in an aqueous medium. The aqueous emulsion, dispersion or suspensionoptionally comprises from about 1% to about 50% (w/w) of oil and fromabout 1% to about 99% (w/w) of the isolated polypeptide composition. Theterm “stable” when used in reference to the emulsions, suspensions anddispersions refers to the ability of the polypeptide fraction describedherein to create a kinetically stable emulsion for the duration of theintended application of the dispersion or emulsion. The terms“emulsion,” “dispersion,” and “suspension” are used interchangeablyherein.

In certain embodiments, the polypeptide composition has a polydispersityindex (PDI) of between about 1 and 1.15. In certain embodiments, the PDIof the adhesives provided created using the polypeptides describedherein is between about 1 and about 3, between 1 and 1.5, between 1.5and 2, between 2 and 2.5, between 2.5 and 3, between 1 and 2, between1.5 and 2.5, or between 2 and 3.

C. Characterization of Water-Soluble Protein Fraction

The water-soluble protein fraction, for example, the water-solubleprotein fraction isolated pursuant to the protocol set forth in FIG. 1,are substantially or completely soluble in water.

The water-soluble protein fraction has one or more of the following sixfeatures. (i) An amide-I absorption band between about 1633 cm⁻¹ and1680 cm⁻¹, as determined by solid state FTIR. (ii) An amide-II bandbetween approximately 1522 cm⁻¹ and 1580 cm⁻¹, as determined by solidstate FTIR. (iii) Two prominent 1° amide N—H stretch absorption bands inthe range of from about 3100-3200 cm⁻¹, and in the range of from about3300-3400 cm⁻¹, as determined by solid state FTIR. (iv) A prominentcluster of protonated nitrogen nuclei defined by ¹⁵N chemical shiftboundaries at about 94 ppm and about 100 ppm, and ¹H chemical shiftboundaries at about 7.6 ppm and 8.1 ppm, as determined by solutionstate, two-dimensional proton-nitrogen coupled NMR. (v) An averagemolecular weight of between about 600 and about 2,500 Daltons, forexample, as determined by MALDI. (vi) An inability to stabilize anoil-in-water or water-in-oil dispersion or emulsion, where the water andoil components of the mixture form an unstable suspension thatmacroscopically phase separates under static conditions within fiveminutes after mixing. This can be tested by dissolving or dispersing 14parts (by weight) of a protein sample of interest in 86 parts (byweight) of water and then mixing the resulting solution with 14 parts(by weight) of oil, for example, PMDI. Under these conditions, awater-soluble protein is characterized by an inability to stabilize anoil-in-water emulsion, where the oil and water components form anunstable suspension that macroscopically phase separates under staticconditions within five minutes after mixing. In certain embodiments, thewater-soluble protein has at least two, three, or four of the abovefeatures.

D. Ground Plant Meal

Plant meal can be obtained from commercial sources or derived from corn,wheat, sunflower, cotton, rapeseed, canola, castor, soy, camelina, flax,jatropha, mallow, peanuts, algae, sugarcane bagasse, tobacco, whey, or acombination thereof. Plant meal can be ground using techniques known inthe art, such as hammer mill (cryogenic or ambient) or ball mill. Incertain embodiments, the plant meal is ground and screened to isolateplant meal particles having a particle size in the range of from about 1μm to about 400 μm, from about 1 μm to about 350 μm, from about 1 μm toabout 300 μm, from about 1 μm to about 250 μm, from about 1 μm to about200 μm, from about 1 μm to about 100 μm, from about 1 μm to about 50 μm,from about 5 μm to about 250 μm, from about 5 μm to about 200 μm, fromabout 5 μm to about 150 μm, from about 5 μm to about 100 μm, from about5 μm to about 50 μm, from about 10 μm to about 250 μm, from about 10 μmto about 100 μm, from about 10 μm to about 90 μm, from about 10 μm toabout 70 μm, from about 10 μm to about 50 μm, from about 20 μm to about150 μm, from about 20 μm to about 100 μm, from about 20 μm to about 80μm, from about 20 μm to about 70 μm, from about 20 μm to about 60 μm,from about 25 μm to about 150 μm, from about 25 μm to about 100 μm, fromabout 25 μm to about 50 μm, from about 50 μm to about 150 μm, or fromabout 50 μm to about 100 μm.

An additive may be added to the plant meal prior to grinding to aid inthe grinding process or produce a ground plant meal with superiorphysical properties for use in manufacturing an adhesive composition,e.g., providing a ground plant meal with improved flow properties,superior packing density, reduced tendency to cake, reduced tendency tobridge, superior particle dispersibility in aqueous mixtures, modulationof particle coupling and/or wetting characteristics with other materialsin the adhesive composition, and the like. Alternatively, the additivemay be added to the plant meal during the grinding process used toproduce ground plant meal.

Additives that impart superior performance properties to the adhesivecomposition or the wood composite formed from the adhesive compositionmay be added to the plant meal before or during grinding or may be addedto the ground plant meal produced from the grinding process. Exemplaryadditives include those described in sections below, and, in particular,include composite-release promoting agents. The additive may be in solidor liquid form, and the additive may be characterized according towhether it reacts with materials in the adhesive composition or does notreact with materials in the adhesive composition.

Exemplary solid additives include (i) inorganic additives such assilica, pigments, catalysts, clays (including intercalated clays,exfoliated clays, and partially exfoliated clays), and the like, and(ii) organic compounds such as fatty acids (e.g., stearic acid, lauricacid), hydrocarbon waxes/liquids, ureas, and fluorocarbon waxes/liquids.Solid additives may be used in amounts ranging, for example, from about0.001% w/w to 40% w/w of the ground plant meal mixture, from about 0.1%w/w to about 20% w/w of the ground plant meal mixture, or from about0.5% w/w to about 15% w/w of the ground plant meal mixture.

Liquid additives may be dry blended with ground plant meal. The amountof liquid additive should be less than that which causes the groundplant meal to cake or bridge during a manufacturing process.Accordingly, in certain embodiments, the amount of liquid additive(s) isless than about 10% by weight of the ground plant meal mixturecontaining the additive(s). In certain other embodiments, the amount ofliquid additive(s) is less than about 5% by weight, or even less thanabout 2% by weight, of the ground plant meal mixture containing theadditive. The liquid additive may be characterized as reactive ornon-reactive. Reactive liquid additives may include organosilanes, lowmolecular weight alcohols such as glycerin or propylene glycol, liquidpolyol oligomers, liquid polyurethane oligomers, addition-polymerizablemonomers, condensation-polymerizable monomers, and reactive oils such asepoxidized soy oil or castor oil.

III. Protein-Bonding Agents

The protein-bonding agent may be an anhydride compound, carboxylic acidcompound, carboxylate salt compound, or a combination thereof. Exemplaryanhydride compounds, carboxylic acid compounds, and carboxylate saltcompounds are described below. In certain embodiments, theprotein-bonding agent is provided in the form of a latex (e.g., anaqueous emulsion). Providing the protein-bonding agent is provided inthe form of a latex can provide advantages in certain situations, suchas (i) allowing incorporation of a high molecular weight polymer withoutsubstantially affecting viscosity of the adhesive composition, and/or(ii) permitting modulation of the Tg of the resulting pressure-sensitiveadhesive.

Physical properties of the adhesive composition, and a solid bindercomposition formed from the adhesive composition, can be adjusted byadjusting the amount of protein-bonding agent in the adhesivecomposition. Accordingly, in certain embodiments, the adhesivecomposition comprises 0.1% (w/w) to about 50% (w/w) protein-bondingagent. In certain other embodiments, the adhesive composition comprisesfrom 0.1% (w/w) to about 20% (w/w) protein-bonding agent. In certainother embodiments, the adhesive composition comprises from 0.1% (w/w) toabout 1.5% (w/w) protein-bonding agent. In certain other embodiments,the adhesive composition comprises from about 0.5% (w/w) to about 1%(w/w) protein-bonding agent, about 3% (w/w) to about 10% (w/w)protein-bonding agent, or about 5% (w/w) to about 20% (w/w)protein-bonding agent.

In certain embodiments, the protein-bonding agent and any optionalpolyol are the only components in the adhesive composition that can forma covalent bond with a protein of the isolated-water soluble proteinfraction. In certain other embodiments, any component capable of forminga covalent bond with the isolated-water soluble protein fraction otherthan said protein-bonding agent and said polyol is present in an amountless than about 10% (w/w), 5% (w/w), or 1% (w/w) of the adhesivecomposition. In certain other embodiments, any component capable offorming a covalent bond with the isolated-water soluble protein fractionother than said protein-bonding agent is present in an amount less thanabout 10% (w/w), 5% (w/w), or 1% (w/w) of the adhesive composition.

Part A: Anhydride Compounds

The term “anhydride compound” refers to a compound containing at leastone —C(O)—O—C(O)— functional group and includes, for example, (i) smallorganic compounds that contain at least one —C(O)—O—C(O)— functionalgroup, oligomers that contain at least one —C(O)—O—C(O)— functionalgroup, and polymers that contain at least one —C(O)—O—C(O)— functionalgroup. Exemplary anhydride compounds useful in the practice of theinvention are described below.

Exemplary small organic compounds containing at least one —C(O)—O—C(O)—functional group include maleic anhydride, phthalic anhydride, succinicanhydride, methacrylic anhydride, glutaric anhydride, citraconicanhydride, isatoic anhydride, diglycolic anhydride, itaconic anhydride,trans-1,2-cyclohexanedicarboxylic anhydride, 2,3-dimethylmaleicanhydride, valeric anhydride, homophthalic anhydride, stearic anhydride,phenylsuccinic anhydride, and 3,4,5,6-tetrahydrophthalic anhydride.

Exemplary classes of anhydride compounds that are small organiccompounds containing at least one —C(O)—O—C(O)— functional groupinclude, for example, compounds represented by formulaR¹—C(O)—O—C(O)—R², wherein R¹ and R² each represent independently foreach occurrence alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl,heteroaryl, aralkyl, or heteroaralkyl, each of which are optionallysubstituted by 1, 2, or more substituents; or R¹ and R² are takentogether with the atoms to which they are attached to form a 3-7membered saturated or unsaturated ring that is optionally substituted by1, 2, or more substituents.

In certain embodiments, the anhydride compound is an anhydride monomer,such as maleic anhydride. In certain other embodiments, the anhydridecompound is an anhydride monomer or a polymer containing an anhydride.

In certain other embodiments, the anhydride compound is a polymercontaining an anhydride. Exemplary classes of polymers containing ananhydride functional group include, for example,poly(alkylvinylether-co-unsaturated anhydride), polyalkylene-unsaturatedanhydride copolymer, and arylalkene-unsaturated anhydride copolymer.Exemplary specific polymers containing an anhydride functional groupinclude, for example, poly(methylvinylether-co-maleic anhydride),polypropylene-maleic anhydride copolymer, polyethylene-maleic anhydridecopolymer, and styrene-maleic anhydride.

Accordingly, in certain embodiments, the anhydride compound is apoly(alkylvinylether-co-unsaturated anhydride), polyalkylene-unsaturatedanhydride copolymer, or arylalkene-unsaturated anhydride copolymer. Incertain other embodiments, the anhydride compound ispoly(methylvinylether-co-maleic anhydride), polypropylene-maleicanhydride copolymer, polyethylene-maleic anhydride copolymer, orstyrene-maleic anhydride copolymer. In certain other embodiments, theanhydride compound is a poly(methylvinylether-co-maleic anhydride).

In certain embodiments, the anhydride compound is a anhydridefunctionalized form of carboxymethyl cellulose, poly(sebacic acid), orpoly(succinic acid).

In certain embodiments, the anhydride compound comprises (i) at leastone anhydride functional group, and (ii) at least one carboxylic acid orcarboxylate functional group. One example of such a compound ispartially hydrolyzed poly(methylvinylether-co-maleic anhydride), whichrefers to poly(methylvinylether-co-maleic anhydride) that has beensubjected to aqueous alkaline conditions in order to convert some (e.g.,at least 5%, 10%, or 25%) of the anhydride groups to carboxylate groups(e.g., an alkali metal carboxylate group). Counterion(s) of thecarboxylate groups can include, for example, metal ions such as Na⁺, K⁺,Ca²⁺, Mg²⁺, Zn²⁺, and Fe²⁺ originating from, for example, metal saltssuch as NaOH and/or Ca(OH)₂. Partially hydrolyzedpoly(methylvinylether-co-maleic anhydride) can provide advantages whenused in an adhesive composition comprising water because, for example,the partially hydrolyzed poly(methylvinylether-co-maleic anhydride) ismore soluble in water than poly(methylvinylether-co-maleic anhydride).Accordingly, in certain embodiments, the anhydride compound is apartially hydrolyzed poly(methylvinylether-co-maleic anhydride).Accordingly, in certain embodiments, the anhydride compound is apartially hydrolyzed poly(methylvinylether-co-maleic anhydride) in whichthe ratio of anhydride groups to carboxylate groups in the range ofabout 20:1 to about 1:1, about 20:1 to about 5:1, or 20:1 to about 10:1.

In certain embodiments, the anhydride compound is a polymer comprising:

(a) at least one

or a salt thereof, wherein x is independently for each occurrence aninteger from 1 to 10, y is independently for each occurrence an integerof from 1 to 10, and z is independently for each occurrence an integerof from 1 to 10; and(b) at least one

wherein a is independently for each occurrence an integer from 1 to 10,b is independently for each occurrence an integer of from 1 to 10, and cis independently for each occurrence an integer of from 1 to 10.

In certain embodiments, the anhydride compound is apoly(methylvinylether-co-maleic anhydride), polypropylene-maleicanhydride copolymer, polyethylene-maleic anhydride copolymer, orstyrene-maleic anhydride copolymer, each of which has partiallyhydrolyzed in order to convert some (e.g., at least 5%, 10%, or 25%) ofthe anhydride groups to carboxylate groups (e.g., an alkali metalcarboxylate group) or carboxylic acid groups.

In certain embodiments, the anhydride compound is a polymer (such as oneof the polymers described above) having a weight average molecularweight in the range of from about 30,000 g/mol to about 3×10⁶ g/mol,about 50,000 g/mol to about 2×10⁶ g/mol, about 100,000 g/mol to about1×10⁶ g/mol, about 1×10⁶ g/mol to about 3×10⁶ g/mol, or about 1.5 toabout 2.5×10⁶ g/mol.

In other embodiments, the anhydride compound is a conjugate formed bybonding (e.g., by grafting) an anhydride group to a naturally occurringcompound. Exemplary naturally occurring compounds suitable for graftinginclude, for example, linseed oil and castor oil.

Physical properties of the adhesive composition, and a solid bindercomposition formed from the adhesive composition, can be adjusted byadjusting the amount of anhydride compound in the adhesive composition.Accordingly, in certain embodiments, the adhesive composition comprisesfrom 0.1% (w/w) to about 50% (w/w) anhydride compound. In certain otherembodiments, the adhesive composition comprises from 0.1% (w/w) to about20% (w/w) anhydride compound. In certain other embodiments, the adhesivecomposition comprises from 0.1% (w/w) to about 1.5% (w/w) anhydridecompound. In certain other embodiments, the adhesive compositioncomprises from about 0.5% (w/w) to about 1% (w/w) anhydride compound.

Part B: Carboxylic Acid Compound

The term “carboxylic acid compound” refers to a compound containing atleast one —CO₂H functional group and includes, for example, (i) smallorganic compounds that contain at least one —CO₂H functional group,oligomers that contain at least one —CO₂H functional group, and polymersthat contain at least one —CO₂H functional group. Exemplary carboxylicacid compounds useful in the practice of the invention are describedbelow.

Exemplary small organic compounds containing at least one —CO₂Hfunctional group include citric acid, sebacic acid, maleic acid,phthalic acid, succinic acid, methacrylic acid, glutaric acid,citraconic acid, isatoic acid, diglycolic acid, itaconic acid,trans-1,2-cyclohexanedicarboxylic acid, 2,3-dimethylmaleic acid, valericacid, homophthalic acid, stearic acid, phenylsuccinic acid, and3,4,5,6-tetrahydrophthalic acid. In certain embodiments, the carboxylicacid compound is a small organic compound that contains 2 or 3 —CO₂Hfunctional groups.

Exemplary classes of carboxylic acid compounds that are small organiccompounds containing one to three —CO₂H functional groups include, forexample, compounds represented by formula R¹—(CO₂H)₁₋₃, wherein R¹ isalkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl,aralkyl, or heteroaralkyl, each of which are optionally substituted by1, 2, or more substituents; or R¹ and R² are taken together with theatoms to which they are attached to form a 3-7 membered saturated orunsaturated ring that is optionally substituted by 1, 2, or moresubstituents

In certain other embodiments, the carboxylic acid compound is a polymercontaining at least one carboxylic acid group. Exemplary classes ofpolymers containing at least one carboxylic acid group include, forexample, naturally occurring polymers that contain at least onecarboxylic acid group, and synthetic polymers that contain at least onecarboxylic acid group. Exemplary specific polymers containing acarboxylic acid group include alginic acid, carboxymethyl cellulose,poly(sebacic acid), poly(succinic acid), poly(glycolic acid),poly(lactic acid), and copolymers of lactic acid and glycolic acid (suchas RESOMER® polymers sold by Evonik Industries). In certain embodiments,the carboxylic acid compound comprises alginic acid, carboxymethylcellulose, poly(sebacic acid), poly(succinic acid), poly(glycolic acid),poly(lactic acid), or a copolymer of lactic acid and glycolic acid.

In embodiments where the carboxylic acid compound is a polymer, thepolymer may have, for example, a weight average molecular weight in therange of from about 30,000 g/mol to about 3×10⁶ g/mol, about 50,000g/mol to about 2×10⁶ g/mol, about 100,000 g/mol to about 1×10⁶ g/mol,about 1×10⁶ g/mol to about 3×10⁶ g/mol, or about 1.5 to about 2.5×10⁶g/mol.

In certain embodiments, the carboxylic acid compound is (i) apolysaccharide containing at least one carboxylic acid group, or (ii) anacrylic acid copolymer. In certain other embodiments, the carboxylicacid compound is alginic acid.

Part C: Carboxylate Salt Compound

The term “carboxylate salt compound” refers to a compound containing atleast one —CO₂ ⁻M⁺ functional group (where M+ is a moiety bearing anpositive charge, such as metal cation like Na⁺, K⁺, Ca²⁺, Mg²⁺, Zn²⁺, orFe²⁺, or a quaternary amine like NH₄ ⁺) and includes, for example, (i)small organic compounds that contain at least one —CO₂ ⁻M⁺ functionalgroup, oligomers that contain at least one —CO₂ ⁻M⁺ functional group,and polymers that contain at least one —CO₂ ⁻M⁺ functional group.Exemplary carboxylate salt compounds useful in the practice of theinvention are described below.

In certain embodiments, the carboxylate salt compound contains at leastone —CO₂ ⁻ M⁺ functional group where M⁺ is a metal cation. In certainother embodiments, the metal cation is selected from the groupconsisting of an alkali metal cation, an alkaline earth metal cation, atransition metal cation, and combinations thereof. In certain otherembodiments, the metal cation is selected from the group consisting ofan alkali metal cation, an alkaline earth metal cation, and combinationsthereof. In certain other embodiments, the metal cation is selected fromthe group consisting of Na⁺, K⁺, Ca²⁺, Mg²⁺, Zn²⁺, Fe²⁺, andcombinations thereof, wherein any divalent metal cation is bonded to twocarboxylate groups. In certain other embodiments, the metal cation isselected from the group consisting of Na⁺, Ca²⁺, and combinationsthereof, wherein Ca²⁺ is bonded to two carboxylate groups. It isappreciated that the definition of M⁺ in —CO₂ ⁻M⁺ results in a compoundthat is charge neutral, such as where if M⁺ is a divalent cation thenthe divalent cation is bonded to (i) two carboxylate groups or (ii) onecarboxylate group and one anion such as —OH or a halogen.

Exemplary small organic compounds containing at least one —CO₂ ⁻M⁺functional group include a citrate salt, sebacate salt, maleate salt,phthalate salt, succinate salt, methacrylate salt, glutarate salt,citraconate salt, isatoic acid salt, diglycolate salt, itaconate salt,trans-1,2-cyclohexanedicarboxylate salt, 2,3-dimethylmaleate salt,valerate salt, homophthalate salt, stearate salt, phenylsuccinate salt,and 3,4,5,6-tetrahydrophthalate salt.

In certain other embodiments, the carboxylate salt compound is a polymercontaining at least one carboxylate salt group. Exemplary classes ofpolymers containing at least one carboxylate salt group include, forexample, naturally occurring polymers that contain at least onecarboxylate salt group, and synthetic polymers that contain at least onecarboxylate salt group. An exemplary specific polymer containing acarboxylic acid group is sodium alginate. In certain embodiments, thecarboxylic acid compound is (i) a polysaccharide containing at least onecarboxylate salt group, or (ii) a copolymer comprising an alkylenecarboxylate salt (such as the sodium or potassium salt of an acrylicacid copolymer). In certain other embodiments, the carboxylate saltcompound is a metal salt of alginate, such as an alkali metal salt ofalginate.

In embodiments where the carboxylate salt compound is a polymer, thepolymer may have, for example, a weight average molecular weight in therange of from about 30,000 g/mol to about 3×10⁶ g/mol, about 50,000g/mol to about 2×10⁶ g/mol, about 100,000 g/mol to about 1×10⁶ g/mol,about 1×10⁶ g/mol to about 3×10⁶ g/mol, or about 1.5 to about 2.5×10⁶g/mol.

In certain embodiments, the carboxylate salt compound is a carboxylatesalt functionalized carboxymethyl cellulose, poly(sebacic acid), orpoly(succinic acid).

IV. Plasticizer

The adhesive compositions may further comprise a plasticizer. Onebenefit provided by the plasticizer is that it may increase the adhesivetack of a solid binder composition formed by curing the adhesivecomposition. Although not wishing to be bound by a particular theory,the plasticizer may increase adhesive tack by lowering the glasstransition temperature of the solid binder composition formed by curingthe adhesive composition.

One exemplary class of plasticizers are polyols. Accordingly, in certainembodiments, the plasticizer is a polyol.

Exemplary specific plasticizers, include, for example, glycerol,sorbitol, glycerol diacetate, ethylphthalyl glycolate,butylphthalylethyl glycolate, butylglycolate, propylene glycol,polyethylene glycol, polyethylene glycol sorbitan monooleate, sorbitanmonooleate, 1,2-propane diol, and 1,3-propane diol. Accordingly, incertain embodiments, the plasticizer is glycerol, sorbitol, glyceroldiacetate, ethylphthalyl glycolate, butylphthalylethyl glycolate,butylglycolate, propylene glycol, polyethylene glycol, polyethyleneglycol sorbitan monooleate, sorbitan monooleate, 1,2-propane diol, or1,3-propane diol. In certain other embodiments, the plasticizer isglycerol.

Physical properties of the adhesive composition, and a solid bindercomposition formed from the adhesive composition, can be adjusted byadjusting the amount of plasticizer in the adhesive composition.Accordingly, in certain embodiments, the adhesive composition comprisesfrom about 1% to about 50% (w/w) of a plasticizer. In certain otherembodiments, the adhesive the composition comprises from about 1% (w/w)to about 30% (w/w) of a plasticizer. In certain other embodiments, theadhesive composition comprises from about 5% (w/w) to about 30% (w/w) ofa plasticizer. In certain other embodiments, the adhesive thecomposition comprises from about 5% (w/w) to about 10% (w/w) of aplasticizer.

V. Water

The adhesive composition may further comprise water. In certainembodiments, the adhesive composition contains an amount of watersufficient to produce the adhesive composition as a liquid (as comparedto a granular mixture). Liquid adhesives can provide advantages, such aseasy of application to a substrate.

The amount of water in the adhesive composition can be selected in orderto achieve certain performance characteristics for the adhesivecomposition. Accordingly, in certain embodiments, water is present in anamount of from about 20% w/w to about 95% w/w of the adhesivecomposition. In certain other embodiments, water is present in an amountof from about 40% w/w to about 60% w/w of the adhesive composition. Incertain other embodiments, water is present in an amount of from about40% w/w to about 80% w/w of the adhesive composition. In certain otherembodiments, water is present in an amount of from about 80% w/w toabout 90% w/w of the adhesive composition. In certain other embodiments,water is present in an amount of from about 35% w/w to about 60% w/w ofthe adhesive composition.

In embodiments where the adhesive composition contains a sufficientamount of water so as to be able to measure the pH of the adhesivecomposition, the adhesive composition may be further characterizedaccording to its pH. In certain embodiments, the adhesive compositionhas a pH in the range of from about 7 to about 10.

VI. Epoxide Compound

The adhesive compositions may optionally further comprise an epoxidecompound. The epoxide compound may undergo reaction with amine groups ofthe protein component, which can modify physical properties of theadhesive composition. In certain embodiments, the epoxide compound is analkyl epoxide, heteroalkyl epoxide, cycloalkyl epoxide, heterocycloalkylepoxide, aryl epoxide, heteroaryl epoxide, aralkyl epoxide, orheteroaralkyl epoxide, each of which are optionally substituted by 1, 2,or more substituents. Additional exemplary epoxide compounds includeepoxidized soy oil and epoxidized linseed oil. The epoxide compound maybe provided in the form of an emulsion, such as an emulsion containingepoxidized soy oil and/or epoxidized linseed oil.

VII. Reactive Prepolymer

The adhesive compositions may optionally comprise a reactive prepolymer.The term “prepolymer” is understood to mean a compound, material ormixture that is capable of reacting with a plant protein compositiondescribed herein to form an adhesive polymer. Exemplary prepolymersinclude, for example, isocyanate-based prepolymers, epoxy-basedprepolymers, and latex prepolymers. Further exemplary prepolymersinclude an organic polyisocyanate; a reaction product between an organicpolyisocyanate and a polypeptide, a polyol, an amine based polyol, anamine containing compound, a hydroxy containing compound, or acombination thereof; an epoxy containing compound; a reaction productbetween an epoxy containing compound and a polypeptide, a polyol, anamine based polyol, an amine containing compound, a hydroxy containingcompound, or a combination thereof; an organosilane; a polymer latex; apolyurethane; and a mixture thereof.

In certain embodiments, the reactive prepolymer is apolyisocyanate-based prepolymer, an epoxy-based prepolymer, alatex-based prepolymer, a latex prepolymer, or a combination thereof.

The term “prepolymer” includes full prepolymers and partial prepolymers(referred to as semiprepolymers, pseudoprepolymers, or quasiprepolymersin certain embodiments). One example of a quasi prepolymer is aNCO-terminated product prepared from a diisocyanate and polyol in whichthe prepolymer is a mixture of (i) a product prepared from thediisocyanate and polyol, and (ii) unreacted diisocyanate. On the otherhand, an example of a full prepolymer is the product formed by reactingan isocyanate with a particular polyol blend so that there aresubstantially no residual monomeric isocyanates in the finished product.

An isocyanate-based prepolymer can be an organic polyisocyanate, whichcan be (i) a polyisocyanate (or monomeric diisocyanate) that has notbeen reacted with another compound, (ii) a polyisocyanate modified byvarious known self-condensation reactions of polyisocyanates, such ascarbodiimide modification, uretonimine modification, trimer(isocyanurate) modification or a combination thereof, so long as themodified polyisocyanate still contains free isocyanate groups availablefor further reaction, or (iii) the product formed by reaction of apolyisocyanate base with a compound having nucleophilic functionalgroups capable of reacting with an isocyanate group. Exemplary compoundscontaining a nucleophilic functional group capable of reacting with anisocyanate group include a polypeptide (for example, one or more of theprotein fractions described herein), a polyol, an amine based polyol, anamine containing compound, a hydroxy containing compound, carboxylicacid containing compound, carboxylate salt containing compound, or acombination thereof. The term “polyisocyanate” refers to difunctionalisocyanate species, higher functionality isocyanate species, andmixtures thereof.

One desirable feature of an isocyanate-based prepolymer is that theprepolymer remain stable enough for storage and use, desirably liquidand of reasonable viscosity at ambient temperatures (25° C.), andcontains free isocyanate (—NCO) groups which can participate in formingadhesive bonds.

As noted above, the organic polyisocyanate can be prepared from a “basepolyisocyanate.” The term “base isocyanate” as used herein refers to amonomeric or polymeric compound containing at least two isocyanategroups. The particular compound used as the base polyisocyanate can beselected so as to provide an adhesive having certain desired properties.For example, base polyisocyanate can be selected based on thenumber-average isocyanate functionality of the compound. For example, incertain embodiments, the base polyisocyanate can have a number-averageisocyanate functionality of 2.0 or greater, or greater than 2.1, 2.3 or2.4. In certain embodiments, the reactive group functionality of thepolyisocyanate component ranges from greater than 1 to several hundred,2 to 20, or 2 to 10. In certain other embodiments, the reactive groupfunctionality of the polyisocyanate component is at least 1.9. Incertain other embodiments, the reactive group functionality of thepolyisocyanate component is about 2. Typical commercial polyisocyanates(having an isocyanate group functionality in the range of 2 to 3) may bepure compounds, mixtures of pure compounds, oligomeric mixtures (animportant example being polymeric MDI), and mixtures of these.

Useful base polyisocyanates have, in one embodiment, a number averagemolecular weight of from about 100 to about 5,000 g/mol, from about 120to about 1,800 g/mol, from about 150 to about 1,000 g/mol, from about170 to about 700 g/mol, from about 180 to about 500 g/mol, or from about200 to about 400 g/mol. In certain other embodiments, at least 80 molepercent or, greater than 95 mole percent of the isocyanate groups of thebase polyisocyanate composition are bonded directly to an aromaticgroup. In certain embodiments, the adhesives described herein have aconcentration of free organically bound isocyanate (—NCO) groups in therange of from about 5% to 35% (w/w), about 7% to 31% (w/w), 10% to 25%(w/w), 10% to 20% (w/w), 15% to 27% (w/w).

In certain embodiments, the base polyisocyanate is an aromaticpolyisocyanate, such as p-phenylene diisocyanate; m-phenylenediisocyanate; 2,4-toluene diisocyanate; 2,6-toluene diisocyanate;naphthalene diisocyanates; dianisidine diisocyanate; polymethylenepolyphenyl polyisocyanates; 2,4′-diphenylmethane diisocyanate(2,4′-MDI); 4,4′-diphenylmethane diisocyanate (4,4′-MDI);2,2′-diphenylmethane diisocyanate (2,2′-MDI);3,3′-dimethyl-4,4′-biphenylenediisocyanate; mixtures of these; and thelike. In certain embodiments, polymethylene polyphenyl polyisocyanates(MDI series polyisocyanates) having a number averaged functionalitygreater than 2 are utilized as the base polyisocyanate.

In certain embodiments, the MDI base polyisocyanate comprises a combined2,4′-MDI and 2,2′-MDI content of less than 18.0%, less than 15.0%, lessthan 10.0%, or less than 5.0%.

In certain other embodiments, the MDI diisocyanate isomers, mixtures ofthese isomers with tri- and higher functionality polymethylenepolyphenyl polyisocyanates, the tri- or higher functionalitypolymethylene polyphenyl polyisocyanates themselves, and non-prepolymerderivatives of MDI series polyisocyanates (such as the carbodiimide,uretonimine, and/or isocyanurate modified derivatives) are utilized aspolyisocyanates for use as the base polyisocyanate. In certain otherembodiments, the base polyisocyanate composition comprises an aliphaticpolyisocyanate (e.g., in a minor amount), e.g., an aliphaticpolyisocyanate comprising an isophorone diisocyanate, 1,6-hexamethylenediisocyanate, 1,4-cyclohexyl diisocyanate, or saturated analogues of theabove-mentioned aromatic polyisocyanates, or mixtures thereof.

In certain other embodiments, the base polyisocyanate comprises apolymeric polyisocyanate, e.g., a polymeric diphenylmethane diisocyanate(polymethylene polyphenyl polyisocyanate) species of functionality 3, 4,5, or greater. In certain embodiments, the polymeric polyisocyanates ofthe MDI series comprise RUBINATE-M® polyisocyanate, or a mixture of MDIdiisocyanate isomers and higher functionality oligomers of the MDIseries. In certain embodiments, the base polyisocyanate product has afree —NCO content of about 31.5% by weight and a number averagedfunctionality of about 2.7.

In certain embodiments, the isocyanate group terminated prepolymers areurethane prepolymers. These can be produced by reaction of ahydroxyl-functional compound with an isocyanate functional compound. Incertain other embodiments, allophanate prepolymers are utilized.Allophanate prepolymers typically require higher temperatures (orallophanate catalysts) to facilitate reaction of the polyol with thepolyisocyanate to form the allophanate prepolymer.

Polyisocyanates used in the compositions described can have the formulaR(NCO)_(n), where n is 2 and R can be an aromatic, a cycloaliphatic, analiphatic, each having from 2 to about 20 carbon atoms. Examples ofpolyisocyanates include, but are not limited to,diphenylmethane-4,4′-diisoeyanate (MDI), toluene-2,4-diisocyanate (TDI),toluene-2,6-diisocyanate (TDI), methylene bis(4-cyclohexylisocyanate(CHMDI), 3-isocyanatomethyl-3,5,5-trimethyl-cyclohexyl isocyanate(IPDI), 1,6-hexane diisocyanate (HDl), naphthalene-1,5-diisocyanate(NDI), 1,3- and 1,4-phenylenediisocyanate,triphenylmethane-4,4′,4″-triisocyanate, polymeric diphenylmethanediisocyanate (PMDI), m-xylene diisocyanate (XDI), 1,4-cyclohexyldiisocyanate (CHDl), isophorone diisocyanate, isomers, dimers, trimersand mixtures or combinations of two or more thereof. The term “PMDI”encompasses PMDI mixtures in which monomeric MDI, for example 4,4′-,2,2′- and/or 2,4′-MDI, is present. PMDI is, in one embodiment, preparedby phosgenation of the corresponding PMDA in the presence of an inertorganic solvent. PMDA is in turn obtained by means of an acidaniline-formaldehyde condensation which can be carried out industriallyeither continuously or batchwise. The proportions ofdiphenylmethanediamines and the homologouspolyphenylpolymethylenepolyamines and their positional isomerism in thePMDA are controlled by selection of the ratios of aniline, formaldehydeand acid catalyst and also by means of a suitable temperature andresidence time profile. High contents of 4,4′-diphenylmethanediaminetogether with a simultaneously low proportion of the 2,4′ isomer ofdiphenylmethanediamine are obtained on an industrial scale by the use ofstrong mineral acids such as hydrochloric acid as catalyst in theaniline-formaldehyde condensation.

The epoxy-based prepolymer can be an epoxide containing compound.Alternatively, the epoxy-based prepolymer can be a reaction productbetween an epoxy and a polypeptide, a polyol, an amine based polyol, anamine containing compound, a hydroxy containing compound, or acombination thereof.

In certain embodiments, the composition is an epoxy resin comprisingfree epoxy groups. Alternatively, the epoxy resin composition isprepared by combining a precursor epoxy resin composition with theisolated and fractionated polypeptide compositions described herein. Theepoxy resin composition can comprise derivatives of digested proteins asdescribed herein.

Epoxy resins refer to molecular species comprising two or more epoxide(oxirane) groups per molecule. Epoxy resins can contain mono-epoxides asreactive diluents, but the main constituents by weight of such resinsare still di- and/or higher functionality species (containing two ormore epoxide groups per molecule).

Epoxy resins useful as precursor epoxy resins can include those whichcomprise difunctional epoxide and/or higher functionality polyepoxidespecies. Precursor epoxy resins include but are not limited todiglycidyl ether of bisphenol-A, diglycidyl ethers of bisphenol-Aalkoxylates, epoxy novolac resins, expoxidized soy oil, epoxidizedlinseed oil, epichlorohydrin, a glycidyl ether type epoxy resin derivedfrom a polyphenol by reaction with epichlorohydrin, and combinationsthereof. In another embodiment, precursor epoxy resins are modified bycombining them with the polypeptide compositions described herein,either in bulk or in aqueous suspension.

The modified epoxy resins can be used in multi-part mixing-activatedadhesive formulations. Alternatively, multi-part formulations cancomprise polyisocyanates and/or known amine based epoxy curatives asadditional components. Alternatively, modified epoxy resins can be usedwith any cure catalysts or other additives known in the epoxy resin art.The polypeptide compositions described herein contain functional groupswhich react with epoxide groups in the epoxy resin. The extent of thisreaction depends upon the preparative conditions, use or non-use ofcatalysts, the specific resins and protein component described hereinselected, etc.

An important subset of epoxy resins can be made by reacting a precursorpolyol with an epihalohydrin, such as epichlorohydrin. The products ofthe reaction are called glycidyl ethers (or sometimes as polyglycidylethers or diglycidyl ethers). In certain embodiments, all the hydroxylgroups in the precursor polyols are converted to the correspondingglycidyl ethers.

An important class of glycidyl ether type epoxy resins are derived frompolyphenols, by reaction with epichlorohydrin. The starting polyphenolsare di- or higher functionality phenols. Industrially important examplesof this type of epoxy resin comprise, for example, diglycidyl ether ofbisphenol-A (also known as DGEB-A); diglycidyl ether of2,6,2′,6′-tetrachloro bisphenol A; diglycidyl ether of bisphenol-F(DGEB-F); epoxidized novolac resins; mixtures of these, and the like.

Partially or fully saturated (hydrogenated) analogs of these epoxyresins may also be used. A non limiting example of a known saturatedepoxy resin of this type is DGEB-H, which is the fully hydrogenated(ring saturated) aliphatic analog of DGEB-A.

Amines, which contain active hydrogen atoms may also be reacted withepichlorohydrin to form epoxy resins. Examples of these types of resinsinclude, for example, N,N,N′,N′-tetraglycidyl diphenylmethane diamine(such as the 4,4′ isomer); p-glycidyloxy-N,N-diglycidylaniline;N,N-diglycidylaniline; mixtures of these; and the like.

Heterocyclic nitrogen compounds that contain active hydrogen atoms maylikewise be converted into the corresponding epoxy resins by reactionwith epichlorohydrin. Non limiting examples of such resins include, forexample, N,N′,N″-triglycidyl isocyanurate;N,N′-diglycidyl-5,5-dimethylhydantoin; mixtures of these; and the like.

Many other kinds of epoxy resins are known which are not made byreaction of an active hydrogen precursor with an epihalohydrin.Non-limiting examples of these types of epoxy resins, known in the art,include, for example, dicyclopentadiene diepoxide (also known as DCPDdioxide), vinycyclohexene diepoxide (dioxide), epoxidizedpolyunsaturated vegetable oils (such as epoxidized linseed oil,epoxidized soy oil, etc.), epoxidized polydiene resins (such asepoxidized polybutadienes), 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methyl cyclohexane carboxylate, mixtures ofthese, and the like. In principle, any precursor molecule which containstwo or more units of reactive aliphatic “C═C” unsaturation per moleculemight be converted into an epoxy resin.

It should be understood that any of the base epoxy resins known in theart, such as those listed above, are frequently modified with diluents,flexibilizers, and/or other additives. The optional possibility of usingone or more known art modifiers or additives, in addition to therequired protein derivatives, is within the level of skill in the art.Those skilled in the art of formulating adhesive systems using epoxyresins will appreciate how and when to use known optional additives andmodifiers.

In addition, the prepolymers can include one, two or more polyolcompounds. Exemplary polyol compounds include an amine alkoxylate,polyoxypropylene glycol, propylene glycol, polyoxyethylene glycol,polytetramethylene glycol, polyethylene glycol, propane diol, glycerin,or a mixture thereof.

Polyols useful in preparing the adhesives described herein include allknown polyols, for example, polyols used in the polyurethanes art. Incertain embodiments, the polyol comprises primary and/or secondaryhydroxyl (i.e., —OH) groups. In certain other embodiments, the polyolcomprises at least two primary and/or secondary hydroxyl (i.e., —OH)groups per molecule. Mono functional alcohols (such as aliphaticalcohols, aromatic alcohols, or hydroxyl functional monomers such ashydroxyl functional acrylates (to yield UV or thermally curablematerials) can be used to cap an isocyanate group. In certain otherembodiments, the polyol comprises a hydroxyl (i.e., —OH) groupfunctionality between 1.6 and 10, between 1.7 to 6, between 2 to 4, orbetween 2 to 3. In certain other embodiments, the weight averagemolecular weight range for the optional polyols is from 100 to 10,000g/mol, from 400 to 6,000 g/mol, or from 800 to 6,000 g/mol.

In certain other embodiments, useful polyols are polyester polyols orpolyether polyols, such as an aliphatic polyether polyol. One exemplaryaliphatic polyether polyol is polyoxypropylene glycol, with a numberaverage molecular weight in the range of from 1,500 to 2,500 g/mol.

In certain embodiments, the total amount of all polyol, or polyols, inthe isocyanate reactive component is from 1% to 80%, or from 3% to 70%,or from 5% to 60% by weight of the total.

In certain other embodiments, alkanolamines comprising primary,secondary, and/or tertiary amine groups can be used.

In certain embodiments, useful water-dispersible polymer latexes caninclude latexes of polymethylmethacrylate and its copolymers, latexes ofpolymethacrylate and its copolymers, latexes of polyvinylchloride andits copolymers, latexes of polyvinylacetate and its copolymers,polyvinyl alcohol and its copolymers, etc.

Further, as discussed above, the prepolymer species can comprise aterminated isocyanate. Here, for example, a polyol is reacted with thebase polyisocyanate composition prior to or during mixing with thepolypeptide fractions herein. Those skilled in the art will recognizemany variations on the use of optional prepolymers in preparing woodadhesive compositions.

The amount of reactive prepolymer used in the adhesive compositions canbe selected based on the desired properties of the adhesive composition.For example, when optimizing the viscosity of a one-part adhesive, theratio of prepolymer (e.g., PMDI, Epoxy and the like) to proteincomponent (i.e., ground plant meal or isolated polypeptide composition)can be from about 10:1 and 4:1 in order to form an adhesive compositionthat is relatively less viscous.

VIII. Additives

One or more additives can be included in the adhesive composition inorder to achieve particular performance properties. Exemplary additivesinclude an intercalated clay, partially exfoliated clay, exfoliatedclay, cellulose nanoparticles, tacking agents, extenders, fillers,viscosifying agents, surfactants, adhesion promoters, antioxidants,antifoaming agents, antimicrobial agents, antibacterial agents,fungicides, pigments, inorganic particulates, gelling agents,cross-linking agents, pH modulators, composite-release promoters, fireretardants, and wood preservatives. In certain embodiments, the additiveis a surfactant, an antioxidant, a fungicide, or a tackifier.

The additive may be characterized according to whether it is awater-dispersible additive or a water-soluble additive. Water-solubleadditives include hydroxyl-functional or amine-functional compounds(such as glycerin, propylene glycol, polypropylene glycol, polyethyleneglycol, trimethylol propane and its adducts, phenols, polyphenols,etc.). One benefit of using glycerin and various low-viscosity polyolsis that they allow less water to be used in the adhesive composition.

In certain embodiments, the additive is a non-volatile (e.g., having aboiling point of greater than about 180° C. at 760 mmHg), inertviscosity-reducing diluent. In yet other embodiments, the additive is anantioxidant, antifoaming agent, anti-bacterial agent, fungicide,pigment, viscosifying agent, gelling agent, aereosolozing agent,inorganic particulate (e.g., titanium dioxide, yellow iron oxide, rediron oxide, black iron oxide, zinc oxide, aluminum oxide, aluminumtrihydrate, calcium carbonate), clay such as montmorillonite, a wettingagent, and the like.

In certain embodiments, the additive is a composite-release promoter(such as a composite-release promoter selected from the group consistingof a C₁₀₋₂₅ alkanoic acid, a salt of a C₁₀₋₂₅ alkanoic acid, a C₁₀₋₂₅alkenoic acid, a salt of an C₁₀₋₂₅ alkenoic acid, and a silicone). Incertain other embodiments, the additive is a pH modulator. In certainother embodiments, the additive is a fire retardant or woodpreservative. In certain other embodiments, the additive is a fireretardant, wood preservative, antimicrobial agent, antibacterial agent,or fungicide, any of which may be in the form of nanoparticles.

Exemplary classes of additives are described in more detail in thesections below.

Intercalated Clay

Intercalated clays can be obtained from commercial sources or preparedby exposing a clay to an intercalating agent. Exemplary types of claythat may be converted to intercalated form include, for example,smectite clays, illite clays, chlorite clays, layered polysilicates,synthetic clays, and phyllosilicates. Exemplary specific clays that maybe converted to intercalated form include, for example, montmorillonite(e.g., sodium montmorillonite, magnesium montmorillonite, and calciummontmorillonite), beidellite, pyrophyllite, talc, vermiculite,sobockite, stevensite, svinfordite, sauconite, saponite, volkonskoite,hectorite, nontronite, kaolinite, dickite, nacrite, halloysite,hisingerite, rectorite, tarosovite, ledikite, amesite, baileychlore,chamosite, clinochlore, kaemmererite, cookeite, corundophilite,daphnite, delessite, gonyerite, nimite, odinite, orthochamosite,penninite, pannantite, rhipidolite, prochlore, sudoite, thuringite,kanemite, makatite, ilerite, octosilicate, magadiite, and kenyaite. Incertain embodiments, the clay converted to intercalated form ismontmorillonite.

Exemplary intercalating agents include, for example, quaternary aminecompounds (such as a tetra-alkylammoniun salt), polymers (e.g., apolycaprolactone, maleated polyethylene, or maleated polypropylene) anacrylic monomer, phosphonium compounds, arsonium compounds, stiboniumcompounds, oxonium compounds, sulfonium compounds, polypropene, fattyacid esters of pentaerythritol, a steroyl citric acid ester, andalcohols (such as aliphatic alcohols, aromatic alcohols (e.g., phenols),aryl substituted aliphatic alcohols, alkyl substituted aromaticalcohols, and polyhydric alcohols).

Intercalated clays can be characterized by, for example, the followingphysical properties: interlayer spacing, d-spacings, clay particle size,particle size distribution, peak degradation temperature, and thicknessof layers. Exemplary physical property features for intercalated clayscontemplated to be amenable for use in the present invention include,for example, one or more of the following: (i) an intercalated clayhaving an interlayer spacing of about 0.5 Å to about 100 Å (or about 1 Åto about 20 Å), (ii) a mean particle size of about 1 μm to about 150 μm(or about 20 μm to about 100 μm), (iii) a particle size distributionwhere about 90 percent to about 50 percent of the intercalated clayparticles have a particle size of from about 20 μm to about 100 μm (orabout 85 percent to about 65 percent of the intercalated clay particleshave a particle size of about 20 μm to about 100 μm), (iv) a peakdegradation temperature of about 200° C. to about 600° C. (or from about300° C. to about 500° C.), and (v) layers in the intercalated clay havea thickness of about 0.5 Å to about 100 Å (or about 5 Å to about 50 Å).

In certain other embodiments, the intercalated clay is intercalatedmontmorillonite having a particle size of less than about 500 nm, orless than about 100 nm. In certain other embodiments, the intercalatedclay is intercalated montmorillonite having a particle size of about 60nm to about 400 nm.

The clay (e.g., an intercalated clay) may be surface treated with anorganic compound, such as a hydrophobic organic compound or hydrophilicorganic compound, in order to promote dispersion of the clay in aformulation, such as an adhesive composition described herein. Surfacetreatment methods and compositions are described in the literature andare contemplated to be amenable for use in the present invention.

Different intercalated clays may impart different performance propertiesto the adhesive composition. Accordingly, in certain embodiments, theintercalated clay is an intercalated smectite. In certain otherembodiments, intercalated clay is a smectite that has been intercalatedwith a quaternary ammonium compound. In certain other embodiments, theintercalated clay is an intercalated montmorillonite. In yet otherembodiments, the intercalated clay is montmorillonite intercalated witha dimethyl-di(C₁₄-C₁₈)alkyl ammonium salt.

Exfoliated Clay & Partially Exfoliated Clay

Exfoliated clay or a partially exfoliated clay can be prepared byexposing an intercalated clay to exfoliation conditions using proceduresdescribed in the literature. One procedure for preparing a partiallyexfoliated clay is to subject an intercalated clay to high shear mixingand/or sonication (e.g., using ultrasound) until the intercalated clayhas partially exfoliated. The procedure may be performed by placing theintercalated clay (e.g., quaternary amine intercalated montmorillonite)in a hydrophobic liquid medium (such as mineral oil, soy oil, castoroil, silicone oil, a terpene (e.g., limonene), plant oil alkyl esters(e.g., soy methyl ester and canola methyl ester), mixtures thereof(e.g., a mixture of a silicone oil and limonene), etc.) to form amixture, and then subjecting the mixture to high shear mixing and/orultrasound until the intercalated clay has partially exfoliated. Partialexfoliation occurs when clay platelets separate from the intercalatedclay particles. Partial exfoliation can be observed macroscopically inmany instances because it can cause a low viscosity mixture ofintercalated clay and hydrophobic liquid medium to form a gel. This gelcan be added to protein adhesives or components used to form a proteinadhesive described herein. Alternatively, the intercalated clay may beadded to a protein adhesive composition, and the protein adhesivecomposition is subjected to exfoliation conditions to generate thepartially exfoliated clay in situ.

An exfoliated clay can be prepared by exposing an intercalated clay tohigh shear mixing and/or sonication (e.g., using ultrasound) untilsubstantially all (e.g., greater than 90% w/w, 95% w/w, or 98% w/w) theintercalated clay has exfoliated. The exfoliation procedure can beperformed by placing the intercalated clay (e.g., quaternary amineintercalated montmorillonite) in a hydrophobic liquid medium (such asmineral oil, soy oil, castor oil, silicone oil, a terpene (e.g.,limonene), plant oil alkyl esters (e.g., soy methyl ester and canolamethyl ester), mixtures thereof (e.g., a mixture of a silicone oil andlimonene), etc.) to form a mixture, and then subjecting the mixture tohigh shear mixing and/or sonication (e.g., using ultrasound) untilsubstantially all the intercalated clay has exfoliated. Alternatively,the intercalated clay may be added to a protein adhesive composition,and the protein adhesive composition is subjected to exfoliationconditions to generate the exfoliated clay in situ. Alternatively, aclay (such as sodium montmorrilonite) may be added to an adhesivecomposition, together with a quaternary ammonium compound, andoptionally together with a satisfactory oil carrier (e.g., one that hasthe ability to solvate the quaternary compound), and the resultingadhesive composition is subjected to conditions to intercalate the clayand to generate the exfoliated clay or partially exfoliated clay insitu. In addition, if so desired, the quaternary ammonium compound canbe pre-dissolved in the oil carrier before it is added to the adhesivecomposition together with a clay.

Exemplary partially exfoliated clays contemplated to be amenable for usein present invention include partially exfoliated forms of smectiteclay, illite clay, chlorite clay, layered polysilicates, synthetic clay,and phyllosilicates. Exemplary specific partially exfoliated clayscontemplated to be amenable for use in present invention includepartially exfoliated forms of, for example, montmorillonite (e.g.,sodium montmorillonite, magnesium montmorillonite, and calciummontmorillonite), beidellite, pyrophyllite, talc, vermiculite,sobockite, stevensite, svinfordite, sauconite, saponite, volkonskoite,hectorite, nontronite, kaolinite, dickite, nacrite, halloysite,hisingerite, rectorite, tarosovite, ledikite, amesite, baileychlore,chamosite, clinochlore, kaemmererite, cookeite, corundophilite,daphnite, delessite, gonyerite, nimite, odinite, orthochamosite,penninite, pannantite, rhipidolite, prochlore, sudoite, thuringite,kanemite, makatite, ilerite, octosilicate, magadiite, and kenyaite. Incertain embodiments, the partially exfoliated clay is partiallyexfoliated clay montmorillonite.

A partially exfoliated clay can be characterized by, for example, theamount of clay particles that are in the form of platelets. In certainembodiments, about 0.1% w/w to about 40% w/w, about 0.1% w/w to about20% w/w, about 0.1% w/w to about 10% w/w, about 0.1% w/w to about 5%w/w, or about 5% w/w to about 20% w/w of the clay particles are in theform of platelets. In certain embodiments, about 0.1% w/w to about 40%w/w of the clay particles are in the form of platelets having a size ofabout 1 Å to about 50 Å, about 30 Å to about 50 Å, or about 5 Å to about20 Å.

Exemplary exfoliated clays contemplated to be amenable for use inpresent invention include exfoliated forms of smectite clay, illiteclay, chlorite clay, layered polysilicates, synthetic clay, andphyllosilicates. Exemplary specific exfoliated clays contemplated to beamenable for use in present invention include exfoliated forms of, forexample, montmorillonite (e.g., sodium montmorillonite, magnesiummontmorillonite, and calcium montmorillonite), beidellite, pyrophyllite,talc, vermiculite, sobockite, stevensite, svinfordite, sauconite,saponite, volkonskoite, hectorite, nontronite, kaolinite, dickite,nacrite, halloysite, hisingerite, rectorite, tarosovite, ledikite,amesite, baileychlore, chamosite, clinochlore, kaemmererite, cookeite,corundophilite, daphnite, delessite, gonyerite, nimite, odinite,orthochamosite, penninite, pannantite, rhipidolite, prochlore, sudoite,thuringite, kanemite, makatite, ilerite, octosilicate, magadiite, andkenyaite. In certain embodiments, the exfoliated clay is an exfoliatedsmectite. In certain embodiments, the exfoliated clay is exfoliatedmontmorillonite.

An exfoliated clay can be characterized by, for example, the size ofplatelets and the aspect ratio of platelets. In certain embodiments, thesize of the platelets is about 1 Å to about 50 Å, about 30 Å to about 50Å, or about 5 Å to about 20 Å. In certain embodiments, aspect ratio ofthe platelets is about 100 to about 10,000, about 100 to about 5,000, orabout 200 to about 2,000. In certain other embodiments, the exfoliatedclay has a mean particle size of less than about 500 nm, less than 100nm, or less than 25 nm. In certain other embodiments, the exfoliatedclay has a mean particle size of from about 60 nm to about 400 nm, about50 nm to about 300 nm, about 40 nm to about 200 nm, or about 20 nm toabout 150 nm.

In certain other embodiments, a partially exfoliated clay is formed byexposing a clay to an effective amount of plant protein composition(e.g., an isolated water-soluble protein fraction or ground plant meal)to form a mixture and subjecting the mixture to exfoliation conditions,such as high shear mixing and/or sonication. In certain otherembodiments, an exfoliated clay is formed by exposing a clay to aneffective amount of plant protein composition (e.g., an isolatedwater-soluble protein fraction or ground plant meal) to form a mixtureand subjecting the mixture to exfoliation conditions, such as high shearmixing and/or sonication.

Cellulose Nanoparticles

Cellulose nanoparticles can be added to the adhesive composition toachieve certain performance properties, such as to provide an adhesivewith increased toughness and/or bond strength. Cellulose nanoparticlescan be obtained from commercial sources or isolated from plant-basedfibers by acid-hydrolysis. Cellulose nanoparticles can be characterizedby, for example, the size of the nanoparticle, the cross-sectional shapeof the nanoparticle, and/or the cross-sectional length and aspect ratioof the nanoparticle. Accordingly, in certain embodiments, the cellulosenanoparticle has a size of from about 1 nm to about 2000 nm, about 10 nmto about 1000 nm, about 10 nm to about 500 nm, or about 10 nm to about200 nm. In certain embodiments, the cross-sectional shape of thenanoparticle may be triangular, square, pentagonal, hexagonal,octagonal, circular, or oval. In certain other embodiments, the averagecross-sectional length of the cellulose nanoparticle is about 0.1 nm toabout 100 nm, or about 1 nm to about 10 nm.

Tacking Agent

Exemplary tacking agents include, for example, glycerin, a terpeneresin, a rosin ester (e.g., pentaerythritol rosin ester, or a glycerolrosin ester), corn syrup, soy oil, a poly(C₂-C₆)alkylene, mineral oil,an ethylene/propylene/styrene copolymer, a butylene/ethylene/styrenecopolymer, or a mixture of one or more of the foregoing. In certainembodiments, the additive is polybutene. In certain embodiments, thepolybutene has a weight average molecular weight of from about 200 g/molto about 20,000 g/mol, from about 200 g/mol to about 10,000 g/mol, fromabout 200 g/mol to about 5,000 g/mol, from about 200 g/mol to about2,000 g/mol, from about 200 g/mol to about 1,000 g/mol, from about 500g/mol to about 2,000 g/mol, or from about 500 g/mol to about 1,000g/mol. Other tacking agents include a solid selected from the groupconsisting of, a rosin ester derivative, and a hydrocarbon-basedderivative. When the tacking agent is a solid, the tacking agent mayoptionally be pre-dissolved in an oil-phase (if present) of the adhesivecomposition (e.g., in PMDI if present). Alternatively, the solid tackingagent can be pre-melted and dispersed in water by means of the proteincomponent, or the solid tacking agent can be ground and dispersed asfine particulates directly into the adhesive composition.

In certain embodiments, the tacking agent is provided as an emulsion,such as an emulsion of terpene resin or a rosin ester.

Extender

Exemplary extenders include, for example, inert extenders or activeextenders. In certain embodiments, the inert extender is vegetableparticulate matter, limonene, vegetable oil, mineral oil, dibasicesters, propylene carbonate, non-reactive modified aromatic petroleumhydrocarbons, soy oil, castor oil, and in general any non-activehydrogen containing liquid that can be incorporated into an isocyanatebased adhesive. Another inert extender is any non-active hydrogencontaining solid that is soluble, e.g., soluble in oil or soluble inwater. The active extender can be a pyrrolidone monomer or polymers, anoxizolidone monomer or polymers, an epoxidized oil, or an unsaturatedoil, such as linseed oil. Another active extender is a vinyl monomer ormixture of vinyl monomers.

Surfactants & Adhesion Promoters

Exemplary surfactants include, for example, monomeric types, polymerictypes, or mixtures thereof. Exemplary adhesion promoters include, forexample, organosilanes and titanates.

Antimicrobial Agent

Antimicrobial agents known in the art that do not substantially reactwith PMDI are contemplated for use in the adhesive compositions andcomposites described herein. One exemplary antimicrobial agent ispolyalkylene glycol polymers, such as polypropylene glycol.

Crosslinking Agent

In other embodiments, the additive can be a crosslinking agent, forexample, a crosslinking agent that can be used to bond lignocellulosicmaterial to glass. Exemplary crosslinking agents include anorganosilane, such as dimethyldichlorosilane (DMDCS),alkyltrichlorosilane, methyltrichlorosilane (MTCS),N-(2-aminoethyl)-3-aminopropyl trimethoxysilane (AAPS), or a combinationthereof. In other embodiments the protein fractions are combined with anorganosilane to form an adhesive for bonding one or more substratestogether in any combination, said substrates including glass, paper,wood, ceramic, steel, aluminum, copper, brass, etc. The term“organosilane” refers to any group of molecules including monomers,hydrolyzed monomers, hydrolyzed dimers, oligomers, and condensationproducts of a trialkoxysilane having a general formula:(RO)₃Si—R′where R is preferably a propyl, ethyl, methyl, isopropyl, butyl,isobutyl, sec-butyl, t-butyl, or acetyl group, and R′ is anorganofunctional group where the functionality may include anaminopropyl group, an aminoethylaminopropyl group, an alkyl group, avinyl group, a phenyl group, a mercapto group, a styrylamino group, amethacryloxypropyl group, a glycidoxy group, an isocyante group, orothers.

Similarly, a bis-trialkoxysilane having the general formula(RO)₃Si—R′—Si(OR)₃ can also be employed as an “organosilane” eitheralone or in combination with a trialkoxysilane, where R is preferably apropyl, ethyl, methyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl,or acetyl group, and R′ is a bridging organofunctional residue which maycontain functionality selected from the group consisting of aminogroups, alky groups, vinyl groups, phenyl groups, mercapto groups, andothers. Similarly, a tetraalkoxysilane having the general formula(RO)₄Si can also be employed as an “organosilane” either alone or incombination with a trialkoxysilane, or a bis-trialkoxysilane, where R ispreferably a propyl, ethyl, methyl, isopropyl, butyl, isobutyl,sec-butyl, t-butyl, or acetyl group.

pH Modulator

The pH modulator can be an acid or base. In certain embodiments, the pHmodulator is an alkali metal hydroxide (e.g., sodium hydroxide) or analkali metal salt of a carboxylate organic compound (e.g., an alkalimetal salt of citrate, such as di-sodium citrate).

Composite-Release Promoter

The composite-release promoter acts to facilitate release of the woodcomposite from the press apparatus used to make the composite. In theabsence of a composite-release promoter, certain composites may stick tothe press apparatus, making it difficult to separate the composite fromthe press apparatus. The composite-release promoter solves this problemby facilitating release of the wood composite. Exemplarycomposite-release promoters include silicones (e.g., silicones describedabove), fatty acids, a salt of a fatty acid, waxes, and amide compounds.Exemplary fatty acids or salts thereof include a C₁₀₋₂₅ alkanoic acid, asalt of a C₁₀₋₂₅ alkanoic acid, a C₁₀₋₂₅ alkenoic acid, a salt of anC₁₀₋₂₅ alkenoic acid; e.g., stearic acid, zinc stearate, lauric acid,oleic acid or a salt thereof (such as an alkali metal salt of oleicacid, such as potassium oleate). It is understood that a mixture of twoor more of the aforementioned exemplary composite-release promoters canalso be used in the adhesive compositions herein. An exemplary amidecompound is N,N′-ethylenebisstearamide. Exemplary waxes include thosedescribed above for the agent that improves moisture resistance, and inparticular, Hexion EW-58H; E Square 165 Amber Petroleum MicrocrystallineWax commercially available from Baker Hughes, Inc.; and Masurf FS 115Emulsion (28% Solids) commercially available from Mason ChemicalCompany. One additional advantage of the protein component in theadhesive composition is that it can facilitate dispersion of thecomposite-release promoter—this feature allows less composite-releasepromoter to be used in the adhesive composition and final compositeproduct. Reducing the amount of composite-release promoter isadvantageous for agents that are relatively more expensive, such ascertain silicone composite-release promoters.

In certain embodiments, the composite-release promoter is a silicone.

Further, in certain embodiments, a composite-release promoter is presentin the final composite at a weight percent in the range of about 0.01%(w/w) to about 5% (w/w), about 0.01% (w/w) to about 2% (w/w), or about0.01% (w/w) to about 1% (w/w).

Additional Polymer Additives

In certain embodiments, the adhesive composition further compriseseither an ethylene copolymer resin, a hydroxyl functionalized polymer,or mixtures thereof. Non limiting examples of suitable ethylenecopolymer resins include ethylene vinyl acetate (EVA),ethylene-co-vinylacetate-co-acrylic acid,ethylene-co-vinylacetate-co-methacrylic acid,ethylene-co-vinylacetate-co-vinylalcohol, carboxylated vinylacetate-ethylene copolymers, and ethylene vinyl alcohol (EVOH) resins.Non-limiting examples of hydroxyl functionalized polymers include watersoluble or partially water soluble polymers such as polyvinylalcohol,polyvinylbutyral-co-vinylalcohol, polyvinylacetate-co-vinylalcohol andthe like; and carbohydrates such as carboxymethylcellulose,ethylmethylcellulose, etc.

The ethylene copolymer can be used as a water dispersion agent (i.e., anEVA latex). The dispersion agent can be a polymer latex containing acarboxylated vinyl acetate-ethylene terpolymer stabilized withpoly-(vinyl alcohol), commercially known as AIRFLEX 426® from AirProducts, Inc. (63% solids by weight). In certain other embodiments, thedispersion agent is Wacker VINNAPAS® 426, which is a carboxylated, highsolids vinyl acetate-ethylene (VAE) copolymer dispersion with a glasstransition temperature (Tg) of 0° C., sold by Wacker Chemie, AG. Theethylene copolymer can be used at a level of from 5% to 50% by weight,from 10% to 40% by weight, or from 15% or 30% by weight of the totalisocyanate reactive component (the level of ethylene copolymer isexpressed on a solids basis, and does not include the level of water inthe latex).

The identity and quantity of ethylene copolymer in the adhesivecomposition may be selected in order to achieve particular performanceproperties for the adhesive composition. For example, the glasstransition temperature (Tg) of a pressure-sensitive adhesive may bemodulated by identity and quantity of ethylene copolymer in the adhesivecomposition.

In certain embodiments, the adhesive composition further comprises alatex polymer. In certain embodiments, the latex polymer is an acrylicacid polymer emulsion, styrene polymer emulsion, vinyl acetate polymeremulsion, ethylene vinyl acetate polymer emulsion, ethyl methacrylatepolymer emulsion, or a carboxylated vinyl acetate-ethylene terpolymeremulsion, such as AIRFLEX 426® or VINNAPAS® 426, as described above).

In certain embodiments, the total amount of latex polymer(s) in theadhesive composition is in the range of from about from 5% to 50% byweight of the adhesive composition, from 10% to 40% by weight of theadhesive composition, or from 15% or 30% by weight of the adhesivecomposition (where the amount of latex polymer is expressed on a solidsbasis, and does not include any water in the latex).

Fire Retardants

Exemplary fire retardants include, for example, (i) phosphoric acid or asalt thereof, such as a mono-ammonium phosphate, di-ammonium phosphate,ammonium poly-phosphate, melamine phosphate, guanidine phosphate, ureaphosphate, alkali metal phosphate, and alkaline earth metal phosphate,(ii) a halogenated phosphate compound, (iii) a phosphate ester, such astri-o-cresyl phosphate and tris(2,3-dibromopropyl) phosphate, (iv) achlorinated organic compound, such as a chlorinated hydrocarbon orchlorinated paraffin, (iv) a brominated organic compound, such as abrominated hydrocarbon, bromo-bisphenol A, tetrabromobisphenol A(TBBPA), decabromobiphenyl ether, octabromobiphenyl ether,tetrabromobiphenyl ether, hexabromocyclododecane,bis(tetrabromophthalimido) ethane, tribromophenol, andbis(tribromophenoxy) ethane, (v) a brominated oligomer or brominatedpolymer, such as TBBPA polycarbonate oligomer, brominated polystyrene,and TBBPA epoxy oligomer, (vi) a borate compound, such as an alkalimetal borate, ammonium borate, or mixture comprising one or more ofborax, boric acid, boric oxide, and disodium octoborate, (vii) aluminiummaterials, such as aluminium trihydrate and aluminium hydroxide, (viii)an alkaline earth metal hydroxide, such as magnesium hydroxide, (ix) analkali metal bicarbonate, such as sodium bicarbonate, (x) an alkalineearth metal carbonate, such as calcium carbonate, (xi) antimonytrioxide, (xii) hydrated silica, (xiii) hydrated alumina, (xiv)dicyandiamide, (xv) ammonium sulfate, and (xvi) a mixture of guanylureaphosphate and boric acid, such as those described in InternationalPatent Application Publication No. WO 02/070215, which is herebyincorporated by reference, (xvii) graphite, (xviii) melamine, and (xix)a phosphonate compound, such as diethyl-N,N-bis(2-hydroxyethyl)aminoethyl phosphonate; dimethyl-N,N-bis(2-hydroxyethyl) aminomethylphosphonate; dipropyl-N,N-bis(3-hydroxypropyl) aminoethyl phosphonate;and dimethyl-N,N-bis(4-hydroxybutyl) aminomethyl phosphonate, such asdescribed in U.S. Pat. No. 6,713,168, which is hereby incorporated byreference.

In certain embodiments, the fire retardant is (i) phosphoric acid or asalt thereof, such as a mono-ammonium phosphate, di-ammonium phosphate,ammonium poly-phosphate, melamine phosphate, guanidine phosphate, ureaphosphate, alkali metal phosphate, and alkaline earth metal phosphate,(ii) a phosphate ester, such as tri-o-cresyl phosphate andtris(2,3-dibromopropyl) phosphate, aluminium trihydrate and aluminiumhydroxide, (iii) an alkaline earth metal hydroxide, such as magnesiumhydroxide, (iv) an alkali metal bicarbonate, such as sodium bicarbonate,(v) antimony trioxide, or (vi) hydrated alumina.

Wood Preservatives

Exemplary wood preservatives include, for example, (i) chromated copperarsenate (CCA), (ii) alkaline copper quaternary, (iii) copper azole,(iv) a borate preservative compound, (v) a sodium silicate-basedpreservative compound, (vi) a potassium silicate-based preservativecompound, (vii) a bifenthrin preservative compound, (viii) a coal-tarcreosote, (ix) linseed oil, (x) tung oil, and (xi) an insecticide, suchas an organochloride compound, organophosphate compound, carbamatecompound, pyrethroid, neonicotinoid, and ryanoid.

IX. General Considerations for Adhesive Compositions

The adhesive composition may be in the form of a liquid or powder.Liquid form adhesives may provide advantages for certain applications,such as where it is desirable to distribute a thin film of adhesive overa large surface area. In certain embodiments, the adhesive compositionis in the form of an aqueous dispersion. Dry blend adhesives may provideadvantages for certain applications, such as those where it is desirableto minimize the amount of volatile compounds (e.g., water) in theadhesive composition. Factors that can affect the viscosity, moistureresistance, bond strength, and other properties of the adhesivecomposition are described below.

Dry Blend Adhesive Compositions

The adhesive composition may be in the form of a dry blend. A first typeof dry blend adhesive composition may be formed by mixing ground plantmeal with one or more liquid or solid additives. The liquid or solidadditives are typically added in an amount less than about 10% w/w ofthe plant meal. Alternatively, the liquid or solid additives are may beblended with the plant meal during grinding to form the ground plantmeal. The ground plant meal containing one or more additives isdesirably a dry and flowable material. Exemplary additives are describedabove in Section VIII, and include intercalated clays, partiallyexfoliated clays, exfoliated clays, mixture of a silicone and a terpenecompound (e.g., limonene), mineral oil, soy oil, castor oil, soy methylester, canola methyl ester urea, glycerin, propylene glycol, propylenecarbonate, polyols, crosslinkers like PMDI, epoxies such as glycidylend-capped poly(bisphenol-A-co-epichlorohydrin) (BPA) andtrimethylolpropane triglycidyl ether, polymer latexes, and catalysts.

A second type of dry blend adhesive composition may be formed by mixingground plant meal with a dry powder ingredient, such as an additive thatis not a liquid (e.g., a clay (such as an intercalated clay, a partiallyexfoliated clay, or an exfoliated clay), or a silicone.

A third type of dry blend adhesive may be formed by mixing the firsttype of adhesive (as described above) with any other dry or liquidingredient that may impart beneficial properties to the adhesivecomposition.

The dry adhesives described above may be used as binders in themanufacture of wood composites. Such wood composites may be prepared byfirst mixing wood particulates with the dry blend adhesive compositionto form a mixture, and then subjecting the mixture to elevatedtemperature and pressure to facilitate densification and curing of theadhesive. The amount of cured adhesive in the wood composite may be, forexample, from about 0.2% and 20% w/w of the cured wood composite.

Amount of Plant Protein Composition

The amount of plant protein composition in the adhesive composition canbe adjusted to achieve particular performance properties. For example,in certain embodiments, the adhesive composition comprises no less thanabout 2%, 5%, 10%, 15%, 20%, 25%, or 30% by weight of the plant proteincomposition (i.e., water-soluble peptide fraction or ground plant meal)described herein (based on the dry weight of the protein component). Themaximum loading of the protein component can be based on, for example,optimizing stability and viscosity. In certain embodiments, the totalconcentration of plant protein composition may be of up to 35% (w/w).Higher viscosity compositions formed from higher weight percentages ofthe plant protein composition described herein can be beneficial inapplications where it is desirable for the uncured adhesive to exhibitcold-tack, flow resistance, sag resistance, and gap-fillingcharacteristics. In certain embodiments, the adhesive compositioncomprises from about 1% to about 5%, about 5% to about 10%, about 10% toabout 20%, about 15% to about 30%, or about 1% to about 10% by weightplant protein composition.

Amount of Non-Volatile Solid Materials

The overall amount of non-volatile solid materials in the adhesivecomposition can be adjusted to achieve particular performanceproperties. For example, in certain embodiments, the adhesivecomposition comprises at least 10% (w/w) non-volatile solid material. Incertain other embodiments, the adhesive composition comprises at least20% (w/w) non-volatile solid material. In certain other embodiments, theadhesive composition comprises at least 50% (w/w) non-volatile solidmaterial.

Viscosity Considerations

In certain embodiments, the viscosity of the adhesive composition is nomore than (NMT) 500,000 cps, NMT 300,000 cps, NMT 200,000 cps, or NMT100,000 cps, NMR 50,000 cps, NMT 25,000 cps, NMT 10,000 cps, or NMT5,000 cps as measured at 25° C. until the adhesive composition is cured.

In order to optimize the viscosity of the adhesive composition, theadhesive composition may contain plant protein composition in an amountsuch that the viscosity of the adhesive formulation increases by no morethan about 25% within about 20 minutes, or no more than about 50% withinabout 20 minutes, after mixing the anhydride and plant proteincomposition. In certain other embodiments, the plant protein compositionis present in an amount such that the viscosity of the adhesiveformulation increases by no more than about 40% within about 30 minutes(or no more than about 40% with about 100 minutes) after mixing theanhydride and plant protein composition. In certain other embodiments,the plant protein composition is present in an amount such that theviscosity of the adhesive formulation remains less than about 1100 cpswithin about 150 minutes after mixing, less than about 1100 cps withinabout 200 minutes after mixing, less than about 1500 cps within about150 minutes after mixing, less than about 1500 cps within about 225minutes after mixing, less than about 50,000 cps within about 150minutes after mixing, less than about 50,000 cps within about 20 minutesafter mixing, less than about 30,000 cps within about 20 minutes aftermixing, less than about 300,000 cps within about 60 minutes aftermixing, or less than about 100,000 cps within about 60 minutes aftermixing the anhydride compound and plant protein composition.

Certain of the adhesives described herein are liquids having viscositieslow enough to render them pourable, sprayable, or curtain-coatable. Forpourable or sprayable adhesive compositions, the viscosity of theadhesive composition is desirably no more than (NMT) 500 cps, NMT 1000cps, NMT 2000 cps, or NMT 5000 cps, as measured at 25° C. The viscosityof the adhesive composition can be optimized by adjusting the amount ofprotein component (i.e., ground plant meal or water-soluble peptidefraction) described herein and/or the conditions used for preparing thecomposition. Alternatively, certain of the adhesives described hereinare non-pourable, extrudable, spreadable gels or pastes. Non-pourable,extrudable, spreadable gels, or pastes may become pourable, sprayable,or curtain-coatable liquids at elevated temperature, and may optionallyrevert to non-pourable, extrudable or spreadable gels or pastes uponcooling.

The adhesive composition can be also characterized according to theweight percent of the plant protein composition (e.g., water-solubleprotein or ground plant meal) in the adhesive composition. In certainembodiments, the plant protein composition is present in an amount fromabout 1% to about 90% (w/w), from about 1% to about 70% (w/w), fromabout 1% to about 50% (w/w), from about 1% to about 30% (w/w), fromabout 10% to about 90% (w/w), from about 10% to about 70% (w/w), fromabout 10% to about 50% (w/w), from about 10% to about 30% (w/w), fromabout 20% to about 90% (w/w), from about 20% to about 70% (w/w), fromabout 20% to about 50% (w/w), or from about 20% to about 30% (w/w) ofthe adhesive composition. In certain other embodiments, the plantprotein composition is present in an amount from about 5% to about 35%(w/w), or from about 5% to about 50% (w/w), of the adhesive composition.

In addition, the plant protein composition (e.g., an isolatedwater-soluble protein fraction or ground plant meal) and the adhesivecomposition can be designed to have a polydispersity index. The term“polydispersity index” refers to the ratio between the weight averagemolecular weight and the number average molecular weight (i.e.,PDI=Mw/Mn).

The terms “number average molecular weight,” denoted by the symbol Mnand “weight average molecular weight,” denoted by the symbol Mw, areused in accordance with their conventional definitions as can be foundin the open literature. The weight average molecular weight and numberaverage molecular weight can be determined using analytical proceduresdescribed in the art, e.g., chromatography techniques, sedimentationtechniques, light scattering techniques, solution viscosity techniques,functional group analysis techniques, and mass spectroscopy techniques(e.g., MALDI mass spectroscopy). For instance, as illustrated in Example2, average molecular weight and number average molecular weight of thepolypeptide composition was determined by MALDI mass spectroscopy.

Further, it is contemplated that plant protein compositions (e.g., anisolated water-soluble protein fraction or ground plant meal) havingdifferent molecular weights may provide adhesive compositions havingdifferent properties. As such, the weight average molecular weight,number average molecular weight, and polydispersity index can be animportant indicator when optimizing the features of the adhesivecomposition. In particular, it is contemplated that the ability tooptimize the molecular weight characteristics of the plant proteincompositions (e.g., an isolated water-soluble protein fraction or groundplant meal) provides advantages when preparing an adhesive compositionfor a particular use. Further advantages include obtaining adhesivecompositions with similar properties even though the protein compositionmay be obtained from a different source (e.g., soy vs. castor) or whensimilar protein sources are harvested during different seasons, overvarying periods of time, or from different parts of the world. Forexample, proteins isolated from soy and castor (each having differentmolecular weight distributions) can be made to have similar molecularweight distributions through digestion and fractionation processesdescribed herein (see Example 2). Accordingly, the ability to measureand control the consistency of molecular weight distributions iscontemplated to be beneficial when optimizing various features of theadhesive composition, e.g., long-term reproducibility of physicalproperties and process characteristics of formulated adhesives. Themolecular weight characteristics of the ground plant meal, water-solubleprotein fraction, or water-insoluble/water-dispersible protein fractioncan be altered by subjecting the proteins therein to enzymatic digestionor fractionation according to the procedures described herein.

In certain embodiments, the PDI of the adhesives provided herein is fromabout 1 to about 3, from 1 to 1.5, from 1.5 to 2, from 2 to 2.5, from2.5 to 3, from 1 to 2, from 1.5 to 2.5, or from 2 to 3.

Tack Strength/Bond Strength

The tack or bond strength of the pressure-sensitive adhesives (PSA) canbe controlled through a number of means, such as shifting the glasstransition (T_(g)) to higher or lower temperatures (by controlling thelevels of monomeric and/or polymeric plasticizers) or incorporatingflatting agents such as silicas, glass spheres, clays, and the like; byadjusting the crosslink density to higher or lower levels; by increasingor decreasing the plasticizer concentration; by blending with higher orlower molecular weight polymers; or by employing some combination ofthese techniques.

It is understood that when evaluating the tack or bond strength of acomposite formed using an adhesive, the maximum achievable strength ofthe composite is dictated by the cohesive strength of the wood itself.To illustrate, if the adhesive is cohesively stronger than the wood,then wood failure will be the outcome. Further, it is contemplated thatthe adhesive composition may be tailored to provide a bond strengthappropriate for particular applications by selecting particular plantprotein composition, prepolymers, catalysts, and/or other additives.

Articles fabricated from one or more of the adhesives described hereincan contain from about 1% to about 15%, or from about 2% to about 10%,or from about 3% to about 8%, or from about 4% to about 7%, or fromabout 3% to about 6% (w/w) of binder (adhesive) per cured article. Incertain embodiments, the article fabricated from the adhesive maycontain greater than 5% (w/w) of binder per cured article. In certainother embodiments, the article comprises from about 1.5% to about 2.5%of binder per cured article.

Composite materials can contain from about 5% to about 85% (w/w), about15% to about 75% (w/w), about 30% to about 65% (w/w), about 1% to about10%, about 10% to about 20%, or about 20% to about 70% (w/w) binder.Laminate materials can contain from about 0.1% to about 10% (w/w), about0.5% to about 5%, about 1% to about 3% (w/w), about 1% to about 10%,about 20% to about 30%, or about 30% to about 70% (w/w) binder.

Adhesive Composition Cure Temperature

Adhesives can be cured by allowing the adhesive to stand under ambientconditions, or the adhesive may be cured by exposing the adhesive toheat, pressure, or both. Furthermore, in certain embodiments, theseadhesives are stable but can cure when exposed to moisture in air. Incertain other embodiments, the adhesive compositions are cold curable.In certain embodiments, the adhesives are cured in the presence ofmoisture at a temperature of about 10° C. to about the ambienttemperature range (25° C., to as high as 30° C.). In certain otherembodiments, the cold cure temperature ranges from 20° C. to 27° C. Inother embodiments, the adhesives are hot cured, at temperatures greaterthan 30° C. Hot curing may occur at temperatures in the range from 50°C. to 150° C., or from 80° C. to 125° C., or from 90° C. to 110° C.

Metals

The adhesive compositions may optionally comprise a metal. In certainembodiments, the composition comprises an alkali metal, an alkalineearth metal, a transition metal, or combination thereof. In certainembodiments, said alkali metal when present is in the form of an alkalimetal salt, an alkali metal hydroxide, or an alkali metal alkoxide; saidalkaline earth metal when present is in the form of an alkaline earthmetal salt, an alkaline earth metal hydroxide, or an alkaline earthmetal alkoxide; and said transition metal when present is in the form ofa transition metal salt, transition metal hydroxide, or transition metalalkoxide.

In other embodiments, the composition comprises an alkali metalhydroxide or an alkaline earth metal hydroxide. In certain embodiments,the alkali metal is sodium or potassium. In certain embodiments, thealkaline earth metal is calcium or magnesium. In certain embodiments,the transition metal is zinc or iron. In certain embodiments, theadhesive composition comprises a sodium salt (e.g., NaCl), sodiumhydroxide, calcium salt (e.g., CaCl₂), calcium hydroxide, or acombination thereof.

Relative Amount of Protein Fractions

Adhesive compositions can be further characterized according to therelative amount of (i) water-soluble protein fraction and (ii)water-insoluble/water-dispersible protein fraction. In certainembodiments, the weight percent ratio of (i) water-soluble proteinfraction to (ii) water-insoluble/water-dispersible protein fraction isat least 1:1, 2:1, 3:1, 4:1, 5:1, 8:1, 10:1, 15:1, or 20:1. In certainembodiments, the adhesive composition is characterized by having (i) atleast 10% (w/w), 15% (w/w), or 20% (w/w) water-soluble protein fraction,and (ii) less than 10% (w/w), 5% (w/w), or 1% (w/w)water-insoluble/water-dispersible protein fraction. In certainembodiments, the adhesive composition is characterized by having (i) atleast 10% water-soluble protein fraction, and (ii) less than 1% (w/w)water-insoluble/water-dispersible protein fraction. In certain otherembodiments, the adhesive composition is characterized by having (i)from about 10% to about 25% (w/w) water-soluble protein fraction, and(ii) less than 1% (w/w) water-insoluble/water-dispersible proteinfraction. In certain other embodiments, the only protein component inthe adhesive composition is water-soluble protein fraction (that is, theadhesive composition does not contain water-insoluble/water-dispersibleprotein fraction).

Combinations

This disclosure describes multiple aspects and embodiments. Allcombinations of such aspects and embodiments are contemplated. Forexample, the adhesive composition may comprise: (a) at least 1% (w/w) ofan isolated water-soluble protein fraction; (b) at least 1% (w/w) of aprotein-bonding agent selected from the group consisting of (i) a metalsalt of alginic acid, (ii) poly(methylvinylether-co-maleic anhydride,and (iii) partially hydrolyzed poly(methylvinylether-co-maleicanhydride); (c) water; and (d) a polyol. In certain embodiments, theadhesive composition comprises from about 5% (w/w) to about 30% (w/w)isolated water-soluble protein fraction. In certain embodiments, theadhesive composition comprises from about 10% (w/w) to about 25% (w/w)isolated water-soluble protein fraction. In certain embodiments, theprotein-bonding agent is a metal salt of alginic acid, such as sodiumalginate. In certain embodiments, the protein-bonding agent selected ispoly(methylvinylether-co-maleic anhydride or partially hydrolyzedpoly(methylvinylether-co-maleic anhydride. In certain embodiments, theadhesive composition comprises from about 1% (w/w) to about 6% (w/w), ormore preferably from about 2% (w/w) to about 5% (w/w), ofprotein-bonding agent. In certain embodiments, the adhesive compositioncomprises from about 30% (w/w) to about 60% (w/w), or more preferablyfrom about 40% (w/w) to about 50% (w/w), water. In certain embodiments,the polyol is glycerin. In certain embodiments, the adhesive compositioncomprises from about 10% (w/w) to about 40% (w/w), or more preferablyfrom about 10% (w/w) to about 20% (w/w) or from about 25% (w/w) to about35% (w/w), polyol. In certain embodiments, the adhesive compositioncomprises sodium or calcium (such as in the form of a sodium cation orcalcium cation). In certain embodiments, the adhesive composition is inthe form of a liquid.

X. Formation of a Solid Binder Composition from the Adhesive Composition

The adhesive compositions may cured to provide a solid bindercomposition. In applications where the solid binder composition is usedas a pressure-sensitive adhesive, it is desirable for the solid bindercomposition to possess adhesive tack at least over a temperature rangeof about 10° C. to about 30° C. The adhesive tack enables the solidbinder composition to adhere to other materials, such as lignocellulosicmaterials.

Accordingly, another aspect of the invention provides a solid bindercomposition formed by curing an adhesive composition described herein.In certain embodiments, the solid binder composition is tacky at leastover a temperature range of about 10° C. to about 30° C. In certainother embodiments, the solid binder composition is tacky at least over atemperature range of about 5° C. to about 30° C., about 15° C. to about30° C., or about 20° C. to about 25° C. In certain embodiments, thesolid binder composition has one or more of the following features: (a)comprises from about 10% to about 40% (w/w) isolated water-solubleprotein fraction; (b) comprises from about 10% to about 80% (w/w)plasticizer; (c) comprises from about 2% to about 25% (w/w)protein-bonding agent (e.g., anhydride compound); (d) the ratio of (i)the weight percent of isolated water-soluble protein fraction in theadhesive composition to (ii) the weight percent of protein-bonding agent(e.g., anhydride compound) in the adhesive composition is from about10:1 to about 1:1; and (e) is tacky at least over a temperature range ofabout 20° C. to about 30° C.

In certain embodiments, the solid binder composition has one or more ofthe following features: (a) comprises from about 10% to about 40% (w/w)isolated water-soluble protein fraction; (b) comprises from about 40% toabout 80% (w/w) plasticizer; (c) comprises from about 2% to about 15%25% protein-bonding agent (e.g., anhydride compound); (d) the ratio of(i) the weight percent of isolated water-soluble protein fraction in theadhesive composition to (ii) the weight percent of protein-bonding agent(e.g., anhydride compound) in the adhesive composition is from about 5:1to about 1:1; and (e) is tacky at least over a temperature range ofabout 20° C. to about 30° C.

The solid binder composition can also be characterized according toperformance in a Bleed Test. In a Bleed Test, the solid bindercomposition is brought into contact with ink, such as ink on a papercoupon, for a period of time at ambient conditions, and then the ink isvisually inspected to determine if the ink bleed to a location differentthan that at the start of the experiment. Desirably, the bindercomposition does not induce visible bleeding of ink in a Bleed Test. Anexemplary Bleed Test is described in Example 12. Ambient conditions are25° C. in the presence of air having, for example, a relative humidityof about 50%. The length of the experiment can be adjusted as desired,such as where the solid binder composition is brought into constantcontact with the ink for period of at least 7 days, 10 days, 14 days, or30 days, before the ink is visually inspected to determine the presenceof any bleeding.

XI. Applications of Adhesive Compositions

The adhesive compositions described herein can be used in a variety ofdifferent applications, which include, for example, bonding togethermany different types of substrates and/or creating composite materials.

Accordingly, the invention provides a method of bonding a first articleto a second article. The method comprises the steps of (a) depositing ona surface of the first article any one of the foregoing adhesivecompositions thereby to create a binding area; and (b) contacting thebinding surface with a surface of the second article thereby to bond thefirst article to the second article. The method optionally alsocomprises the step of, after step (b), permitting the adhesivecomposition to cure, which can be facilitated by the application ofpressure, heat or both pressure and heat.

The adhesive compositions can be applied to the surfaces of substratesin any conventional manner. Alternatively, the surfaces can be coatedwith the composition by spraying, or brushing, doctor blading, wiping,dipping, pouring, ribbon coating, combinations of these differentmethods, and the like.

The invention also provides a method of producing a composite material.The method comprises the steps of (a) combining a first article and asecond article with any one of the foregoing adhesive compositions toproduce a mixture; and (b) curing the mixture produced by step (a) toproduce the composite material. The curing can comprise applyingpressure, heat or both pressure and heat to the mixture.

The terms “substrate”, “adherend” and “article” are interchangeable andrefer to the substances being joined, bonded together, or adhered usingthe methods and compositions described herein. In certain embodiments,the first article, the second article or both the first and secondarticles are lignocellulosic materials, or composite materialscontaining lignocellulosic material. Furthermore, the first article, thesecond article or both the first and second articles can comprise ametal, a resin, a ceramic, a polymer, a glass or a combination thereof.In certain other embodiments, the first article and the second articleare independently paper or cardboard. It is understood that the firstarticle, the second article, or both the first article and the secondarticle can be a composite.

The compositions can be used to bond multiple lignocellulosic materials(adherends) together to prepare composite wood products. Furthermore, itis understood that at least one of the adherends bonded together and/orincluded in the composite can be wood, wood fiber, paper, rice hulls,fiberglass, ceramic, ceramic powder, plastic (for example, thermosetplastic), cement, stone, cloth, glass, metal, corn husks, bagasse, nutshells, polymeric foam films or sheets, polymeric foams, fibrousmaterials, or combinations thereof.

The amount of adhesive composition applied to the adhesive bond betweensubstrates may vary considerably from one end use application, or typeof adhesive used, or type of substrate, to the next. The amount ofadhesive should be sufficient to achieve the desired bond strength andbond durability under a given set of test conditions.

The amount of an adhesive composition applied may be in the range offrom about 5 to about 50 grams per square foot, from about 8 to about 60grams per square foot, from about 10 to about 30 grams per square foot,from about 20 to about 50 grams per square foot, from about 15 to about40 grams per square foot, of bond surface area (i.e., the bond surfacearea being the area of overlap between the substrates to be bonded bythe adhesive composition).

The adhesive compositions can be used to fabricate multi-substratecomposites or laminates, particularly those comprising lignocellulosicor cellulosic materials, such as wood or paper. The adhesives can beused to prepare products such as plywood, laminated veneer lumber (LVL),waferboard (also known as chipboard or OSB), particle board, fiberboard,fiberglass, composite wooden I-beams (I-joists), and the like.

The adhesive compositions can also be used to fabricate compositematerials, which include, for example, chip board, particle board, fiberboard, plywood, laminated veneer lumber, glulam, laminated whole lumber,laminated composite lumber, composite wooden I-beams, medium densityfiberboard, high density fiberboard, extruded wood, or fiberglass. Thecomposite can be a thermosetting composite or a thermoplastic composite.As described above, the amount and identity of the components used toprepare the composite can be selected to optimize the performanceproperties of the composite. In one embodiment, the amount of proteincomponent is selected in order to optimize the performance properties ofthe composite.

Viscosity, sprayability, and/or spreadability of the adhesive componentscan be controlled by adjusting the amount of water added (or otherliquid diluents such as glycerin and corn syrup).

Articles of Manufacture

Another aspect of the invention provides an article produced by themethods described above. In certain embodiments, the article comprises(i) a substrate and (ii) a pressure-sensitive adhesive formed by curingan adhesive composition (described herein) on the substrate. In certainembodiments, the substrate is a lignocellulosic substrate, such as paperor cardboard.

Yet other embodiments of the invention provide an article produced usingan adhesive composition described herein. In certain embodiments, thearticle comprises a lignocellulosic component. In certain embodiments,the article comprises paper, wood, glass, fiberglass, wood fiber,ceramic, ceramic powder, or a combination thereof.

Another aspect of the invention provides an article comprising two ormore components bonded together using the adhesive composition describedherein. In certain embodiments, the bonded components are selected fromthe group consisting of paper, wood, glass, metal, fiberglass, woodfiber, ceramic, ceramic powder, plastic, and a combination thereof. Incertain embodiments, the article is a composite. In certain otherembodiments, the composite is a random non-oriented homogeneouscomposite, an oriented composite, or a laminated composite. In certainother embodiments, the composite is chip board, particle board, fiberboard, oriented strand board, plywood, laminated veneer lumber, glulam,laminated whole lumber, laminated composite lumber, composite woodenI-beams, medium density fiberboard, high density fiberboard, extrudedwood, or fiberglass. In certain other embodiments, the composite is athermosetting composite or a thermoplastic composite. In certain otherembodiments, the article is a particle board composite.

XII. Definitions

To facilitate an understanding of the present invention, a number ofterms and phrases are defined below.

As used throughout, the term “isolated” refers to material that isremoved from its original environment (e.g., the natural environment ifit is naturally occurring). For example, removal of water-solubleprotein from plant material (such as soy plant meal or soy proteinisolate, each of which contain a mixture of components) in order toprovide the water-soluble protein in substantially pure form results ina water-soluble protein fraction that is “isolated” (i.e., isolatedwater-soluble protein fraction). “Substantially pure” refers to materialhaving a purity of at least 90% (w/w) (or more preferably at least 95%(w/w) or 98% (w/w)).

The term “Bleed Test” refers to an assay to visually determine if inkmigrates from its original location on an article to a new location onsaid article over a period of time, such as, at least 1 day, 3 days, 7days, 10 days, 14 days, or 30 days. One example of a Bleed Test involvesbringing a solid binder composition into contact with ink, such as inkon a coupon, for a period of time at ambient conditions, and then theink is visually inspected to determine if the ink migrated to a locationdifferent than that at the start of the experiment (i.e., whether theink “bleed”). The period of time is desirably 7 days or 14 days.

The term “alkyl” as used herein refers to a saturated straight orbranched hydrocarbon, such as a straight or branched group of 1-12,1-10, or 1-6 carbon atoms, referred to herein as C₁-C₁₂alkyl,C₁-C₁₀alkyl, and C₁-C₆alkyl, respectively. Exemplary alkyl groupsinclude, but are not limited to, methyl, ethyl, propyl, isopropyl,2-methyl-1-propyl, 2-methyl-2-propyl, 2-methyl-1-butyl,3-methyl-1-butyl, 2-methyl-3-butyl, 2,2-dimethyl-1-propyl,2-methyl-1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl,2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl,2,2-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl, butyl,isobutyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl,etc.

The term “cycloalkyl” as used herein refers to a monovalent saturatedcyclic, bicyclic, or bridged cyclic (e.g., adamantyl) hydrocarbon groupof 3-12, 3-8, 4-8, or 4-6 carbons, referred to herein, e.g., as“C₄₋₆cycloalkyl,” derived from a cycloalkane. Exemplary cycloalkylgroups include, but are not limited to, cyclohexane, cyclopentane,cyclobutane, and cyclopropane.

The term “aryl” as used herein refers to refers to a mono-, bi-, orother multi-carbocyclic, aromatic ring system. Unless specifiedotherwise, the aromatic ring is optionally substituted at one or morering positions with substituents selected from alkanoyl, alkoxy, alkyl,alkenyl, alkynyl, amido, amidino, amino, aryl, arylalkyl, azido,carbamate, carbonate, carboxy, cyano, cycloalkyl, ester, ether, formyl,halogen, haloalkyl, heteroaryl, heterocyclyl, hydroxyl, imino, ketone,nitro, phosphate, phosphonato, phosphinato, sulfate, sulfide,sulfonamido, sulfonyl and thiocarbonyl. The term “aryl” also includespolycyclic ring systems having two or more cyclic rings in which two ormore carbons are common to two adjoining rings (the rings are “fusedrings”) wherein at least one of the rings is aromatic, e.g., the othercyclic rings may be cycloalkyls, cycloalkenyls, cycloalkynyls, and/oraryls. Exemplary aryl groups include, but are not limited to, phenyl,tolyl, anthracenyl, fluorenyl, indenyl, azulenyl, and naphthyl, as wellas benzo-fused carbocyclic moieties such as 5,6,7,8-tetrahydronaphthyl.In certain embodiments, the aryl group is not substituted, i.e., it isunsubstituted.

The term “aralkyl” as used herein refers to an aryl group having atleast one alkyl substituent, e.g. -aryl-alkyl-. Exemplary aralkyl groupsinclude, but are not limited to, arylalkyls having a monocyclic aromaticring system, wherein the ring comprises 6 carbon atoms. For example,“phenylalkyl” includes phenylC₄alkyl, benzyl, 1-phenylethyl,2-phenylethyl, etc.

The term “heteroaryl” as used herein refers to aromatic groups thatinclude at least one ring heteroatom. In certain instances, a heteroarylgroup contains 1, 2, 3, or 4 ring heteroatoms. Representative examplesof heteroaryl groups includes pyrrolyl, furanyl, thiophenyl, imidazolyl,oxazolyl, thiazolyl, triazolyl, pyrazolyl, pyridinyl, pyrazinyl,pyridazinyl and pyrimidinyl, and the like. The heteroaryl ring may besubstituted at one or more ring positions with, for example, halogen,azide, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxyl,amino, nitro, sulfhydryl, imino, amido, carboxylic acid, —C(O)alkyl,—CO₂alkyl, carbonyl, carboxyl, alkylthio, sulfonyl, sulfonamido,sulfonamide, ketone, aldehyde, ester, heterocyclyl, aryl or heteroarylmoieties, —CF₃, —CN, or the like. The term “heteroaryl” also includespolycyclic ring systems having two or more rings in which two or morecarbons are common to two adjoining rings (the rings are “fused rings”)wherein at least one of the rings is heteroaromatic, e.g., the othercyclic rings may be cycloalkyls, cycloalkenyls, cycloalkynyls, and/oraryls.

The terms “heterocyclyl” or “heterocyclic group” are art-recognized andrefer to saturated, partially unsaturated, or aromatic 3- to 10-memberedring structures, alternatively 3- to 7-membered rings, whose ringstructures include one to four heteroatoms, such as nitrogen, oxygen,and sulfur. Heterocycles may also be mono-, bi-, or other multi-cyclicring systems. A heterocycle may be fused to one or more aryl, partiallyunsaturated, or saturated rings. Heterocyclyl groups include, forexample, biotinyl, chromenyl, dihydrofuryl, dihydroindolyl,dihydropyranyl, dihydrothienyl, dithiazolyl, homopiperidinyl,imidazolidinyl, isoquinolyl, isothiazolidinyl, isoxazolidinyl,morpholinyl, oxolanyl, oxazolidinyl, phenoxanthenyl, piperazinyl,piperidinyl, pyranyl, pyrazolidinyl, pyrazolinyl, pyridyl, pyrimidinyl,pyrrolidinyl, pyrrolidin-2-onyl, pyrrolinyl, tetrahydrofuryl,tetrahydroisoquinolyl, tetrahydropyranyl, tetrahydroquinolyl,thiazolidinyl, thiolanyl, thiomorpholinyl, thiopyranyl, xanthenyl,lactones, lactams such as azetidinones and pyrrolidinones, sultams,sultones, and the like. Unless specified otherwise, the heterocyclicring is optionally substituted at one or more positions withsubstituents such as alkanoyl, alkoxy, alkyl, alkenyl, alkynyl, amido,amidino, amino, aryl, arylalkyl, azido, carbamate, carbonate, carboxy,cyano, cycloalkyl, ester, ether, formyl, halogen, haloalkyl, heteroaryl,heterocyclyl, hydroxyl, imino, ketone, nitro, phosphate, phosphonato,phosphinato, sulfate, sulfide, sulfonamido, sulfonyl and thiocarbonyl.In certain embodiments, the heterocycicyl group is not substituted,i.e., it is unsubstituted.

The term “carboxylate” as used herein refers to —C(O)O-M, wherein M is acation, such as an alkali metal cation (e.g., Na⁺ or K⁺) or an ammoniumgroup (e.g., N(R*)₄ ⁺ where R* represents independently for eachoccurrence hydrogen, alkyl, aryl, aralkyl, etc.

In embodiments where it is indicated that a chemical group issubstituted with a substituent, exemplary substituents include, forexample, alkanoyl, alkoxy, alkyl, alkenyl, alkynyl, amido, amidino,amino, aryl, arylalkyl, azido, carbamate, carbonate, carboxy, cyano,cycloalkyl, ester, ether, formyl, halogen, haloalkyl, heteroaryl,heterocyclyl, hydroxyl, imino, ketone, nitro, phosphate, phosphonato,phosphinato, sulfate, sulfide, sulfonamido, sulfonyl and thiocarbonyl,unless indicated otherwise.

The terms “amine” and “amino” are art-recognized and refer to bothunsubstituted and substituted amines, e.g., a moiety that may berepresented by the general formula:

wherein R⁵⁰ and R⁵¹ each independently represent hydrogen, alkyl,alkenyl, or —(CH₂)_(m)—R⁶¹; or R⁵⁰ and R⁵¹, taken together with the Natom to which they are attached complete a heterocycle having from 4 to8 atoms in the ring structure; wherein R⁶¹ is aryl, cycloalkyl,cycloalkenyl, a heterocycle or a polycycle; and m is zero or an integerin the range of 1 to 8. In certain embodiments, R⁵⁰ and R⁵¹ eachindependently represent hydrogen or alkyl.

The terms “alkoxyl” or “alkoxy” are art-recognized and refer to an alkylgroup, as defined above, having an oxygen radical attached thereto.Representative alkoxyl groups include methoxy, ethoxy, propyloxy,tert-butoxy and the like. An “ether” is two hydrocarbons covalentlylinked by an oxygen. Accordingly, the substituent of an alkyl thatrenders that alkyl an ether is or resembles an alkoxyl, such as may berepresented by one of —O-alkyl, —O-alkenyl, —O-alkynyl,—O—(CH₂)_(m)—R⁶¹, where m and R⁶¹ are described above.

The term “amide” or “amido” as used herein refers to a radical of theform —R_(a)C(O)N(R_(b))—, —R_(a)C(O)N(R_(b))R_(c)—, —C(O)NR_(b)R_(c), or—C(O)NH₂, wherein R_(a), R_(b) and R_(c) are each independently selectedfrom alkoxy, alkyl, alkenyl, alkynyl, amide, amino, aryl, arylalkyl,carbamate, cycloalkyl, ester, ether, formyl, halogen, haloalkyl,heteroaryl, heterocyclyl, hydrogen, hydroxyl, ketone, and nitro. Theamide can be attached to another group through the carbon, the nitrogen,R_(b), R_(c), or R_(a). The amide also may be cyclic, for example R_(b)and R_(c), R_(a) and R_(b), or R_(a) and R_(c) may be joined to form a3- to 12-membered ring, such as a 3- to 10-membered ring or a 5- to6-membered ring. The term “carboxamido” refers to the structure—C(O)NR_(b)R_(c).

Throughout the description, where compositions are described as having,including, or comprising specific components, or where processes andmethods are described as having, including, or comprising specificsteps, it is contemplated that, additionally, there are compositions ofthe present invention that consist essentially of, or consist of, therecited components, and that there are processes and methods accordingto the present invention that consist essentially of, or consist of, therecited processing steps.

As a general matter, compositions specifying a percentage are by weightunless otherwise specified. Further, if a variable is not accompanied bya definition, then the previous definition of the variable controls.

The description herein describes multiple aspects and embodiments of theinvention. The patent application contemplates all combinations of theaspects and embodiments, such as where one or more embodiments arecombined, such as where a particular water-soluble protein fraction iscombined with a particular protein-bonding agent (e.g., an anhydridecompound) to form an adhesive composition.

Additional adhesive compositions, methods of making adhesivecompositions, methods of using adhesive compositions, and articles aredescribed in U.S. patent application Ser. Nos. 12/719,521; 13/154,607;and 13/154,607; the contents of which are hereby incorporated byreference.

Practice of the invention will be more fully understood from theforegoing examples, which are presented herein for illustrative purposesonly, and should not be construed as limiting the invention in any way.

EXAMPLES Example 1: Isolation of Polypeptide Compositions

Exemplary procedures for isolating and characterizing thewater-insoluble polypeptide composition, water-soluble polypeptidecomposition, or a mixture thereof are described below.

Procedure A: Preparation of Water-Insoluble Polypeptide Composition andPreparation of Water-Soluble Polypeptide Composition.

Everlase digested protein from castor (experimental sample lot 5-90) wasobtained from Prof. S. Braun at the Laboratory of the Department ofApplied Biology at the Hebrew University of Jerusalem, Israel. Digestedcastor can be prepared as follows: castor meal protein is suspended inwater at the ratio of about 1:10 w/w. Calcium chloride is added to aneffective concentration of about 10 mM, and the pH of the suspensionadjusted to pH 9 by the addition of 10 N NaOH. The reaction is thenheated to 55° C. while stirring. Next, Everlase 16L Type EX®(NOVOZYMES') is added at the ratio of 20 g per kg of castor mealprotein, and the mixture is stirred at the same temperature for about 4hours. Finally, the resulting mixture is brought to a pH 3.5 with citricacid and spray-dried to provide a powder.

The Everlase digested protein from castor (lot 5-90) was fractionated toyield a water-soluble fraction, and a water-insoluble, dispersiblefraction. In the first step, 300 g of digested castor was slurried into1 liter of distilled water. The mixture was shaken by hand, and was thenplaced into a sonicator bath for a period of 30 minutes. The slurry thenwas removed and was allowed to set idle for a period of up to two daysto allow the insoluble portion to settle (in separate experiments, itwas found that centrifuging was equally adequate). At that point, theclear yellow/amber supernatant was pipetted away and was retained forfuture use. Fresh distilled water was then added to the sediment tobring the total volume back to the 1-Liter mark on the container. Theprocess of shaking, sonicating, settling, supernatant extracting, andreplenishing with fresh distilled water (washing) then was repeated (6times in total). In the final step, the water was pipetted from the topof the grayish-black sediment, and the sediment was then dried in avacuum oven at 45° C. Based on the sediment's dry weight, thewater-insoluble/water-dispersible polypeptide fraction was determined tocomprise of approximately 50% by weight of the digested castor.Separately, the 1^(st) and 2^(nd) supernatants were combined and werethen dried to yield a transparent yellow-colored, water-solublepolypeptide fraction.

After drying the fractions, it was verified that the grayish-blacksediment (the water-insoluble and dispersible fraction) could not bere-dissolved in water. On the other hand, the dried supernatant fraction(clear/amber, glassy solid) was completely soluble in water.

The two fractions were separately analyzed by solid state FTIR (seeFIGS. 2-4). The spectra in FIG. 2 show that carboxylate and amine saltmoieties are primarily associated with the water-soluble fraction. FIG.3 shows that the amide carbonyl stretch band and the amide N—H bendbands are shifted to higher wavenumbers in the water-soluble polypeptidefraction. These components also appear to be present in thewater-insoluble dispersible polypeptide fraction, but the predominantamide-I and amide-II bands are shifted to lower wavenumbers. Aside fromhydrogen bonding effects, these differences also appear to be related tothe presence of a higher fraction of primary amide groups in thewater-soluble polypeptide fraction, and to a higher fraction ofsecondary amide groups in the water-dispersible polypeptide fraction(from the main-chain polypeptide chains). This is corroborated by theN—H stretching region depicted in FIG. 4.

FIG. 4 shows solid state FTIR spectra of isolated fraction from digestedcastor where the N—H stretching region from FIG. 2 is expanded. Thespectra were vertically scaled to achieve equivalent absorbanceintensities for the secondary amide N—H stretch band centered at 3275cm⁻¹. FIG. 4 shows that the predominant type of amide in thewater-dispersible fraction is the secondary main-chain amide asevidenced by the single, highly symmetric band centered at 3275 cm⁻¹.Although the water-soluble fraction also contains this type of amide, italso contains significantly higher fractions of primary amides asevidenced by the presence of the two primary N—H stretching bands atapproximately 3200 cm⁻¹ (symmetric) and at approximately 3300 cm⁻¹(asymmetric), respectively.

These spectra show that the water-soluble polypeptide fraction containeda relatively high concentration of primary amines, free carboxylicacids, acid salts, and amine salts. Conversely, thewater-insoluble/water-dispersible polypeptide fraction had a higherfraction of secondary amides. In addition, the amide-I carbonylabsorption band for the water-insoluble/water-dispersible fraction wasobserved to appear at a wavenumber of approximately 1625 cm⁻¹, whereasthat of the water-soluble fraction was observed at approximately 1640cm⁻¹. As will be discussed elsewhere, this feature is one of thedistinguishing differences between the water-soluble and water-insolublepolypeptide fractions; not only for castor proteins, but for soyproteins and canola proteins as well.

Procedure B: Additional Procedure for Preparation of Water-InsolublePolypeptide Composition and Preparation of Water-Soluble PolypeptideComposition.

Digested soy protein was obtained as an experimental sample (lot 5-81)from Prof. S. Braun, the Laboratory of Applied Biology at the HebrewUniversity of Jerusalem, Israel. The digested soy protein was preparedas follows. Soy protein isolate (Soy protein isolate SOLPRO 958® SolbarIndustries Ltd, POB 2230, Ashdod 77121, Israel) was suspended in waterat a ratio of 1:10 (w/w). The pH of the suspension was adjusted to pH 7with 10N NaOH, and was then heated to 55° C. while stirring. Neutrase0.8 L® (NOVOZYMES') then was added at a ratio of 20 g per kg of soyprotein, and the mixture was stirred at the same temperature for 4hours. The resulting mixture (pH 6.5) was spray-dried to yield a lighttan powder.

Digested soy (lot 5-81) was fractionated to yield a water-solublepolypeptide fraction, and a water-insoluble/water-dispersiblepolypeptide fraction. In the first step, 300 g of digested soy wasslurried into 1 liter of distilled water. The mixture was shaken byhand, and was then placed into a sonicator bath for a period of 30minutes. Aliquots were placed into centrifuge tubes, and the tubes werethen spun at 3,400 rpm for a period of approximately 35 minutes. Thecentrifuged supernatant, which contained the water-soluble fraction, wasdecanted off of the remaining water-insoluble sediment, and was pouredinto a separate container for later use (this clear yellow supernatantwas placed into an open pan and was allowed to evaporate dry at atemperature of 37° C.). After the first washing step, fresh distilledwater was then added to the tubes, and the remaining sediment wasdispersed into the water by means of hand-stirring with a spatula. Thecombined centrifugation, decanting, and re-dispersion procedures wereperformed for a total of 5 cycles. After the final cycle, the freeliquid containing residual water-soluble protein was decanted from theresidual paste-like dispersion (yellowish-peach in color). The resultingdispersion (gravimetrically determined to be 16.24% solids by weight)contained the water-insoluble/water-dispersible proteins.

The paste-like dispersion was observed to be stable for a period ofseveral weeks. It was also discovered that the dispersion could bereadily combined with water-soluble polymers, and with water-dispersiblepolymer latexes. Moreover, the dispersion was readily compatible withPMDI (a stable dispersion was formed when PMDI was added to the slurry,and there was no evidence of PMDI phase separation, even after 24hours). By contrast, neither the water soluble extract from the digestedsoy, nor the digested soy itself was capable of stabilizing a dispersionof PMDI in water.

After drying aliquots of both fractions, it was verified that the yellowsediment (the water-insoluble/water-dispersible extract) could not bere-dissolved in water. On the other hand, the dried supernatant fraction(clear/yellow solid) was completely soluble in water. The two driedextracts were separately analyzed by solid state FTIR (see FIGS. 5-8).FIG. 6 shows overlaid solid state FTIR spectra of isolated fractionsfrom digested soy, where the N—H region is expanded. The spectra werevertically scaled to achieve equivalent absorbance intensities for thesecondary amide N—H stretch band centered at 3275 cm⁻¹. FIG. 6 showsthat the predominant type of amide in the water-dispersible fraction isthe secondary main-chain amide as evidenced by the single, highlysymmetric band centered at 3275 cm⁻¹. Although the water-solublepolypeptide fraction also contains this type of amide, it also containssignificantly higher fractions of primary amides as evidenced by thepresence of the two primary N—H stretching bands at approximately 3200cm⁻¹ (symmetric) and at approximately 3300 cm⁻¹ (asymmetric),respectively. Collectively, these spectra revealed that thewater-soluble polypeptide fraction was comprised of a relatively highconcentration of primary amines Conversely, the water-insoluble,dispersible polypeptide fraction was comprised of a higher fraction ofsecondary amines.

As shown in FIG. 5, the amide carbonyl stretch band and the amide N—Hbend band are shifted to higher wavenumbers in the water-solublefraction. These components also appear to be present in thewater-insoluble dispersible fraction, but the predominant amide-I andamide-II bands are shifted to lower wavenumbers. Aside from hydrogenbonding effects, these differences appear to be related to the presenceof a higher fraction of primary amide groups (and/or primary amines) inthe water-soluble polypeptide fraction (from lower molecular weightamino acid fragments), and to a higher fraction of secondary amidegroups in the water-dispersible polypeptide fraction (from themain-chain polypeptide chains). This is supported by the N—H stretchingregion depicted in FIG. 4.

FIG. 6 shows that the predominant type of amide in the water-dispersiblefraction is the secondary main-chain amide as evidenced by the single,highly symmetric band centered at 3275 cm⁻¹. Although the water-solublefraction also contains this type of amide, it also containssignificantly higher fractions of primary amines as evidenced by thepresence of the two primary N—H stretching bands at 3200 cm⁻¹(symmetric) and at approximately 3300 cm⁻¹ (asymmetric), respectively.

In spite of being derived from different plant sources, thewater-insoluble dispersible fractions from digested soy and digestedcastor are spectrally similar to one another (see FIG. 12). Conversely,the water-soluble polypeptide fractions appear to have different FTIRspectral characteristics (see FIG. 10). Further, MALDI massspectroscopic indicates the water-soluble polypeptide fractions fromdigested soy and digested castor have different molecular weightcharacteristics. The commonality between the two types of water-solublefractions is that they both appear to contain primary amines/amides.

Procedure C: Additional Procedure for Preparation of Water-InsolublePolypeptide Composition and Preparation of Water-Soluble PolypeptideComposition

Castor meal (4.0 kg containing 24.8% protein) was suspended in 0.1M NaOHat a 10:1 w/w meal to alkali ratio. The suspension was stirred for 18hours at ambient temperature and the solids were then removed bycentrifugation. The supernatant (about 32 liters) was acidified to pH4.5 with 10 N HCl. The protein was allowed to sediment at about 10° C.for 12 hours, the clear supernatant solution was decanted, and the heavyprecipitate (about 2 kg) was collected by centrifugation. The wetprecipitate was freeze-dried yielding 670 g protein isolate.

The water-insoluble and water-soluble polypeptide fractions wereobtained by means of extraction with water. In the first step, 10 g ofthe castor protein isolate (lot 5-94) was slurried into 50 g ofdistilled water. The mixture was dispersed via mechanical stirring for 2hours. Aliquots then were placed into centrifuge tubes, and the tubeswere then spun at 3,400 rpm for a period of approximately 35 minutes.The centrifuged supernatant, which contained the water-soluble fraction,was decanted from the remaining water-insoluble sediment, and was pouredinto a separate container (this clear yellow supernatant was saved anddried at 37° C. for subsequent dispersion experiments and solid stateFTIR analyses). After the first washing step, fresh distilled water wasthen added to the tubes, and the remaining sediment was dispersed intothe water by means of hand-stirring with a spatula. The combinedcentrifugation, decanting, and re-dispersion procedures were performedfor a total of 13 cycles. After the final cycle, the free liquid wasdecanted from the residual paste-like dispersion (the water-insolublepolypeptide fraction from the starting castor protein). Upon drying, thepaste was determined to contain 28.58% solids, and the total yield ofthe water-insoluble fraction was determined to be 62.87%. Thus, thestarting castor protein itself contained 62.87% water-insolublepolypeptide material, and 37.12% water-soluble polypeptide material.

Procedure D: Preparation of Digested Whey Protein.

Digested whey protein (lot 5-72, referred to herein as digested wheyprotein pH 6.5) was obtained as an experimental sample from Prof. S.Braun, the Laboratory of Applied Biology at the Hebrew University ofJerusalem, Israel, and was prepared as follows; Whey protein (WPI-95®Whey Protein Isolate; Nutritteck, 24 Seguin Street, Rigaud, QC, CanadaJOP 1P0) was suspended in water at a ratio of 1:6 (w/w). The pH of thesuspension was adjusted to pH 7 with 5N NaOH, and was heated to 55° C.while stirring. FLAVOURZYME 500MG® (from NOVOZYMES') then was added at aratio of 20 g per kg of whey protein, and the mixture was stirred at thesame temperature for 4 hours. The resulting aqueous mixture was pH 6.5.The resulting mixture then was spray-dried to yield digested wheyprotein as a pale yellow powder containing a mixture of water-solubleand water-insoluble polypeptide.

Procedure E: Preparation of Digested Castor Protein Reacted with SodiumNitrite.

Castor meal protein was suspended in water at a ratio of 1:10 (w/w).Calcium chloride was added at an effective concentration of 10 mM, andthe pH of the suspension was adjusted to pH 9 by the addition of 10 NNaOH. The reaction was heated to 55° C. while stirring. Everlase 16LType EX® (NOVOZYMES') then was added at a ratio of 10 g per kg of castormeal protein, and the mixture was stirred at the same temperature for 4hours. L-lactic acid (90%, 120 g per kg castor protein) then was addedto bring the mixture to pH 4.4 followed by gradual addition (over a 20hour period) of sodium nitrite solution in water (0.4 kg/1, 0.4 literper kg castor protein) while stirring. The reaction then was left tostand at ambient temperature for 40 hours. Na₂S₂O₅ (0.2 kg per kg castorprotein) was then added, and the reaction was heated to 60° C. andstirred for 15 minutes. After cooling to ambient temperature, thereaction was brought to pH 2.0 with concentrated HCl. It was then leftat 10° C. for 18 hours, and the resulting precipitate was separated bycentrifugation for 15 minutes at 24,000×g. The precipitate wasre-suspended in 10 mM citric acid (3 vol. per vol. precipitate), andthen it was collected and subsequently freeze-dried to yield a tanpowder containing a mixture of water-soluble and water-insolublepolypeptide.

Procedure F: Isolation of Water-Insoluble/Water-Dispersible ProteinFraction and Water-Soluble Protein Fraction by Washing Ground Soy Mealwith Water, and Characterization of Same

Part I: Isolation of Water-Insoluble/Water-Dispersible Protein Fractionand Water-Soluble Protein Fraction

Soy meal (same as Example 1) having a particle size range of 20-70 μmwas mixed with distilled water (pH approximately 7) to yield a 27.83%meal dispersion in water (w/w). In the first “wash” step, an aliquot ofthe dispersion was centrifuged for 60 minutes, and the clear supernatantcontaining a water-soluble protein fraction was decanted from the wetslurry that remained on the bottom of the centrifuged tube (in aseparate experiment, this wet slurry was gravimetrically determined tocontain approximately 33% solids in water (w/w); and the supernatant wasgravimetrically determined to contain approximately 15% by weight solids(w/w)). The yield of the water-insoluble/water-dispersible proteinfraction after the first “wash” step was determined to be approximately80% of the starting meal weight.

In a second step, the 33% solids fraction from the first wash step wasmixed and dispersed in fresh distilled water (pH approximately 7), andthe dispersion was centrifuged for a second time. Again, the clearsupernatant was decanted, and the remaining slurry was subjected to athird wash cycle (addition of fresh distilled water followed bycentrifuging). After the third “wash” step and supernatant decanting,the resulting slurry of water-insoluble/water-dispersible proteinfraction was gravimetrically determined to contain approximately 24%solids, and the yield was determined to be approximately 53% of thestarting meal weight. Thus, the ground soy meal itself was comprised ofapproximately 53% of a water-insoluble/water-dispersible proteinfraction, and approximately 47% of a water-soluble protein fraction.

Part II: Dispersion Analysis for Water-Insoluble/Water-DispersibleProtein Fraction, Water-Soluble Protein Fraction, and Ground Soy Meal

An aliquot of the 24% solids dispersion of the isolatedwater-insoluble/water-dispersible protein fraction (washed 3 times asnoted above) was blended with PMDI at a w/w ratio of 1 part PMDI to 1part of protein fraction. The resulting mixture formed a stabledispersion, and remained stable during a 1 hour period of observationwith no visual signs of phase separation.

In order to test dispersion ability of ground soy meal, a dispersion of24% (w/w) ground soy meal in water was mixed with PMDI at a 1:1 w/wratio of PMDI to soy meal solids. The soy meal comprised approximately53% by weight of a water-insoluble/water-dispersible protein fractionand approximately 47% by weight of a water-soluble protein fraction. Themixture of ground meal and PMDI formed a stable dispersion whichremained stable during a 1 hour period of observation with no visualsigns of phase separation.

In order to test dispersion ability of water-soluble protein faction,water-soluble protein fraction obtained from the soy meal (by firstwashing the soy meal, then isolating the water-soluble fraction bydrying the supernatant after centrifuging) was dissolved in water toyield a 24% solids solution (w/w). When PMDI was added to this solution(at a 1:1 weight ratio of PMDI to water-soluble protein fraction), theresulting mixture was unstable, and phase separation was visuallyevident—immediately after mixing.

The experimental results above demonstrate that water-emulsifiedPMDI-containing adhesive compositions can be prepared with i)water-insoluble/water-dispersible protein fractions obtained by washingground plant meals, and ii) ground plant meal compositions that arecomprised of both a water-insoluble/water-dispersible protein fractionand a water-soluble protein fraction. The water-soluble protein fractiondoes not facilitate dispersion, but thewater-insoluble/water-dispersible protein fraction is present in anamount sufficient to facilitate dispersion.

Various commercially available compositions derived from plant meals,such as soy flour, are solvent-extracted which result in removal ofwater-insoluble protein components. Such compositions are unable tofacilitate dispersion, and, thus, are less desirable for use making anadhesive.

Part III: FTIR Analysis of Water-Insoluble/Water-Dispersible ProteinFraction, Water-Soluble Protein Fraction, and Ground Soy Meal

Solid state surface ATR FTIR experiments were performed onwater-insoluble/water-dispersible protein fraction (this sample wascollected after the third wash cycle and was allowed to dry at 23° C.,and water-soluble protein fraction (this sample was collected from theclear supernatant after the third wash cycle, and was allowed to dry at23° C. to yield a transparent amber solid) obtained by washing soy mealwith water. Characteristics of the FTIR spectra are described below.

FIG. 16 shows the solid state FTIR spectra for the isolatedwater-insoluble/water-dispersible protein fraction from soy mealtogether with the water-soluble protein fraction where the N—Hstretching region has been expanded. The spectra were vertically scaledto achieve equivalent absorbance intensities for the secondary amide N—Hstretch band centered at 3275 cm⁻¹. FIG. 16 shows that the predominanttype of amide in the water-insoluble/water-dispersible protein fractionis the secondary main-chain amide as evidenced by the single, highlysymmetric band centered near 3275 cm⁻¹. Although the water-solublefraction also contains this type of amide, it also containssignificantly higher fractions of primary amides as evidenced by thepresence of the two primary N—H stretching bands at approximately 3200cm⁻¹ (symmetric) and at approximately 3300 cm⁻¹ (asymmetric),respectively.

As shown in FIG. 17, the amide-I carbonyl absorption band for thewater-insoluble/water-dispersible protein fraction was observed toappear at a wavenumber of approximately 1629 cm⁻¹, whereas that of thewater-soluble protein fraction was observed to appear at approximately1650 cm⁻¹. This feature is one of the distinguishing differences betweenthe water-soluble protein fraction and water-insoluble/water-dispersibleprotein fraction, not only for isolated polypeptides from castor and soyproteins, but for protein-containing fractions that are isolateddirectly from plant meals like soy meal. Moreover, the amide-II band forthe water-insoluble/water-dispersible protein fraction was observed toappear as a broad band centered at approximately 1526 cm⁻¹, whereas thatof the water-soluble protein fraction was observed to appear atapproximately 1580 cm⁻¹ together with a weak shoulder at approximately1547 cm⁻¹.

Example 2: Characterization of Polypeptide Compositions by MassSpectrometry

This Example describes characterization of the various protein samplesvia MALDI Mass Spectrometry using an Ultraflex III instrument fromBruker.

The instrument was set in positive mode, in order to detect positiveions generated during the ionization process. The voltage applied toaccelerate the ion into the TOF analyzer was set at 25 KV. The analysiswas carried out by using the instrument in reflection mode whichimproves the resolution. Solid samples were dissolved in DMSO at aconcentration of 10 mg/mL. Water-soluble supernatant fractions whichwere solvated in water.

Each sample solution was mixed with a matrix solution (for analyticalpurposes). The matrix was an inert compound of low molecular weightwhich absorbs at the same wavelength of the laser, Nd:YAG 355 nm. Thematrices used were: α-CHCA, alpha-cyano-4-hydroxycinnamic acid,dissolved in a solution of ACN/H₂O (70:30) with 0.1% of TFA at aconcentration of 10 mg/mL; and DCTB,T-2-[3-(4-t-Butyl-phenyl)-2-methyl-2-propenylidene]malononitrile,dissolved in THF at a concentration of 10 mg/mL. The first matrix wasmainly used for the analysis of peptides and proteins while the secondone, DCTB, was suitable for the analysis of polymers.

The matrix solutions and the sample solutions were mixed at a 10:1volume ratio respectively. For the analysis where DCTB was used asmatrix, NaTFA (10 mg/mL in THF) was added to the solution matrix/sampleas a cationizing agent at a ratio 10:2:1 by volume (matrix:sample:salt,respectively). 0.8 μL of the resulting solutions were spotted on atarget plate made of polished steel, and only after the solvents werecompletely dried was the target loaded into the instrument. The spectrawere collected and manipulated by using FlexAnalysis software releasedby Bruker Daltonics.

Relative fragment intensities were normalized and used to calculatenumber average (Mn), weight average (Mw), and z-average (Mz) molecularweight parameters for various samples. The results are summarized inTable 2.

TABLE 2 Sample ID Mn Mw Mz Mw/Mn Castor protein isolate lot 5-94¹ 11491162 1179 1.01 Digested castor lot 5-83² 951 1081 1250 1.13 Digestedcastor lot 5-108³ 897 1011 1169 1.12 Digested castor Water-insoluble/1009 1371 1928 1.35 dispersible fraction (lot 5-108)³ Digested castorWater-soluble fraction 1532 1697 1894 1.10 (lot 5-108)³ Soy ProteinIsolate 2023 2104 2161 1.03 Digested Soy (lot 5-81)⁴ 894 989 1104 1.10Digested Soy Water-insoluble/dispersible 910 1119 1512 1.22 fraction(lot 5-81)⁴ Digested Soy Water-soluble fraction 837 888 941 1.06 (lot5-81)⁴ ¹see Example 1, Procedure C ²Castor meal protein digested withEverlast (Lot No. 5-83) was obtained from Prof. Sergei Braun of TheHebrew University of Jerusalem ³see Example 4 ⁴see Example 1, ProcedureB

The results indicate that the molecular weight characteristics (asdetermined by MALDI mass spectroscopy) of the polypeptide compositioncan depend on the process used to obtain the polypeptide composition.For example, castor protein isolate was observed to have a higher numberaverage molecular weight than its digested counterpart. Further, upondigestion, the number average molecular weight was observed to decreasewhile the polydispersity increased. The same trend was observed for thesoy protein isolate and its digested counterpart.

Other experimental results indicate that proteins in the water-solublepolypeptide composition from digested castor have a higher numberaverage molecular weight than its parent protein isolate. However,proteins in the water-soluble polypeptide composition from digested soyhad a lower number average molecular weight than its parent soy proteinisolate.

Collectively, these results indicate that it is possible to preparecompositions that both i) have particular molecular weight features, andii) have the ability to disperse an oil in water or water in oil, byselecting a particular procedure for preparing the polypeptidecomposition.

Example 3: Characterization of Polypeptide Compositions byTwo-Dimensional Proton-Nitrogen NMR Correlation Spectra andCharacterization of a Water-Insoluble/Water-Dispersible PolypeptideFraction

The water-insoluble and water-soluble protein fractions were prepared asfollows. Digested castor (lot 5-83) was suspended in water at the ratioof 1:10 w/w. Calcium chloride was added to the effective concentrationof 10 mM, and the pH of the suspension was adjusted to pH 9 by theaddition of 10 N NaOH. The reaction was heated to 55° C. while stirring.Everlase 16L Type EX® (NOVOZYMES') then was added at the ratio of 10 gper kg of castor meal protein, and the mixture was stirred at the sametemperature for 4 hours. The resulting mixture then was brought to a pH3.5 with citric acid and was spray-dried to yield a tan powder. Then,the water-insoluble and water-soluble protein fractions were harvestedas described in Example 1 (Procedure A) and were allowed to air-dry at23° C.

The dried powder containing the water-insoluble protein fraction wasdissolved in d6-DMSO (6.8% by weight) to yield a red homogeneoussolution (Sample A). An aliquot of the as-made dried digested castor wasalso dissolved in d6-DMSO (6.8% solids by weight) to yield a comparativehomogeneous red solution (Sample B). Solid-state FTIR analyses of thesame dried powders revealed distinct differences in both the N—Hstretching and carbonyl stretching regions of the solid state FTIRspectra. These spectral differences were attributed to differences inbonding environments for the polypeptide N—H moieties, possiblyresulting from differences in secondary and tertiary structure. One ofthe specific differences involved a shift to lower wavenumbers for theamide-I carbonyl band in the water-insoluble/water-dispersible fraction.In order to further characterize these types of differences, atwo-dimensional NMR technique was employed for the purpose ofcharacterizing a very specific subset of bonded atomic nuclei; namely,protons bonded to nitrogens.

The samples were dissolved in DMSO-d6 and were placed into 5 mm NMRtubes. All ¹H NMR spectra were recorded on a Varian NOVA 750 MHzspectrometer equipped with an HCN-PFG (pulsed field gradient) tripleresonance Cryo Probe at 30° C. For one-dimensional (1D) ¹H NMR spectra,a spectral window of 10000 Hz was used with an acquisition time of 3seconds and relaxation delay of 5 seconds. The spectra were signalaveraged for 16 transients using a proton 90° pulse width of 8.6microseconds. The spectral data were zero filled to 132k points and wereprocessed with 1 Hz line broadening, then baseline corrected andreferenced to an internal residual solvent DMSO-d6 peak at 2.50 ppmbefore integrating and making plots.

Phase sensitive two-dimensional (2D) ¹H-¹⁵N gradient-HSQC (heteronuclearsingle quantum coherence) data were collected with 2048 acquisitionpoints in the F2 dimension and 768 points in the F1 dimension (90° pulsewidths of 6.3 microseconds, and 33.5 microseconds were used for protonand nitrogen, respectively) 48 transients were collected for eachincrement, with a repetition delay of 1.2 seconds and acquisition timeof 0.124 seconds with GARP decoupling during acquisition. The acquireddata were processed with sine bell weighting and zero filled to8196×8196 points in F2 and F1 dimensions before final transformation toproduce the 2D correlation data.

The results are presented in FIGS. 13-15. FIG. 13 represents thetwo-dimensional HSQC ¹H-¹⁵N NMR spectrum for digested castor lot 5-83 ind6-DMSO. The y-axis represents ¹⁵N chemical shift scale (ppm), and thex-axis represents ¹H chemical shift scale (ppm). The peaks within thespectrum represent protonated nitrogen atoms from all of the fractionsthat were present within the as-made digested castor (i.e., thewater-insoluble/water-dispersible polypeptide fractions plus thewater-soluble polypeptide fractions). The multiple peaks in region Bwere observed to disappear upon removal of the water-soluble fractions(see FIG. 14). This indicates that these protonated nitrogens arespecific to the water-soluble polypeptide fractions, whereas at least aportion of the peaks in region A are specific to thewater-insoluble/water-dispersible fraction.

FIG. 14 represents the two-dimensional HSQC ¹H-¹⁵N NMR spectrum for thewater-insoluble/water-dispersible polypeptide extract from digestedcastor lot 5-83 in d6-DMSO. The y-axis represents ¹⁵N chemical shiftscale (ppm), and the x-axis represents ¹H chemical shift scale (ppm).The peaks within the spectrum represent protonated nitrogen atoms fromthe water-insoluble/water-dispersible polypeptide fraction. The peakswithin Region B were observed to be very weak in comparison to theanalogous peaks within the digested castor before extraction (see FIG.13). Conversely, the remaining peaks were predominantly from theprotonated nitrogens in Region A. This indicates that these particularprotonated nitrogens are specific to the water-insoluble polypeptidefractions. A magnified view of this region is presented in FIG. 15.

As shown in FIG. 14, the peaks within the spectrum represent protonatednitrogen atoms that are specific to thewater-insoluble/water-dispersible polypeptide fraction. Upon expansion,the two “peaks” appear as narrow clusters that can be readily defined bythe ¹⁵N and ¹H chemical shift boundaries that define them: the ¹⁵Nboundaries for both clusters occur at approximately 86.2 ppm and 87.3ppm; and the ¹H boundaries occur at approximately 7.14 and 7.29 ppm forthe first cluster; and at approximately 6.66 and 6.81 ppm for the secondcluster.

The results of these studies revealed that while the water-solublepolypeptide fraction was composed of multiple types of protonatednitrogen atoms (see FIG. 13), the water-insoluble/water-dispersiblefraction contained significantly fewer types of protonated nitrogens,and was predominantly characterized by the presence of two majorproton-nitrogen cross peak clusters (see FIG. 14). These differences,like those as seen by solid state FTIR, illustrate that the chemicalbonding environments within the water-soluble polypeptide fraction aredistinctly different from those that exist within thewater-insoluble/water-dispersible fraction.

Together, the solid state FTIR and NMR data characterize thewater-insoluble/water-dispersible polypeptide fraction, where there is asolid-state infrared amide-I absorption band between 1620-1632 cm⁻¹; asolid-state infrared amide-II absorption band between 1514-1521 cm⁻¹;and a solution-state pair of protonated nitrogen clusters as determinedby a ¹H-¹⁵N nuclear magnetic resonance correlation technique. Morespecifically, when the pair of protonated nitrogen clusters is observedby means of NMR with deuterated d6-DMSO as the solvent using atwo-dimensional HSQC ¹H-¹⁵N NMR technique, the clusters are defined bythe ¹⁵N and ¹H chemical shift boundaries that define them: the ¹⁵Nboundaries for both clusters occur at approximately 86.2 ppm and 87.3ppm; and the ¹H boundaries occur at approximately 7.14 and 7.29 ppm forthe first cluster; and at approximately 6.66 and 6.81 ppm for the secondcluster.

Together, the solid state FTIR and NMR data also characterize thewater-soluble polypeptide fraction, where there is a solid-stateinfrared amide-I absorption band between about 1633-1680 cm⁻¹; asolid-state infrared amide-II absorption band between 1522-1560 cm⁻¹;two prominent 1° amide N—H stretch absorption bands centered at about3200 cm⁻¹, and at about 3300 cm⁻¹, as determined by solid state FTIR,and a prominent cluster of protonated nitrogen nuclei defined by ¹⁵Nchemical shift boundaries at about 94 ppm and at about 100 ppm, and ¹Hchemical shift boundaries at about 7.6 ppm and at about 8.1 ppm, asdetermined by solution state, two-dimensional proton-nitrogen coupledNMR.

Example 4: Oil Dispersion Characteristics of Water-Soluble andWater-Insoluble/Water-Dispersible Protein Fractions

A water-insoluble/water-dispersible polypeptide fraction and awater-soluble polypeptide fraction were isolated from digested castor(lot 5-108) based on procedures described in Example 1 (Procedure A).The digested castor can be prepared as follows: castor meal protein issuspended in water at the ratio of about 1:10 w/w. Calcium chloride isadded to an effective concentration of about 10 mM, and the pH of thesuspension adjusted to pH 9 by the addition of 10 N NaOH. The reactionis then heated to 55° C. while stirring. Next, Everlase 16L Type EX®(NOVOZYMES') is added at the ratio of 10 g per kg of castor mealprotein, and the mixture is stirred at the same temperature for about 4hours. Finally, the resulting mixture is brought to a pH 3.5 with citricacid and spray-dried to provide a powder.

The MALDI fragmentation molecular weight characteristics of the isolatedfractions are provided in Example 2. The solid state FTIR spectroscopicabsorption characteristics for the isolatedwater-insoluble/water-dispersible polypeptide fraction conform withthose as described in FIGS. 2-4, 7, and 9-12 (amide-I absorption range:1620-1632 cm⁻¹; amide-II absorption range: 1514-1521 cm⁻¹). Solutionstate two-dimensional proton-nitrogen coupled NMR on the isolatedwater-insoluble/water-dispersible polypeptide fraction show twoprotonated nitrogen clusters enveloped by ¹⁵N chemical shift boundariesat approximately 86.2 ppm and 87.3 ppm; and with ¹H chemical shiftboundaries at approximately 7.14 and 7.29 ppm for the first cluster; andat approximately 6.66 and 6.81 ppm for the second cluster. Solutionstate two-dimensional proton-nitrogen coupled NMR on the isolatedwater-soluble polypeptide fraction show a cluster of protonated nitrogennuclei defined by ¹⁵N chemical shift boundaries at about 94 ppm and atabout 100 ppm, and ¹H chemical shift boundaries at about 7.6 ppm and atabout 8.1 ppm.

The water-insoluble/water-dispersible polypeptide fractions with thesespectral characteristics (unlike their water-soluble counterparts)exhibit the unique ability to emulsify and stabilize dispersions of oilin water and water in oil. This unique oil-dispersing capability isobserved with water-insoluble/water-dispersible polypeptide compositionsthat are extracted and isolated from multiple sources, including but notlimited to (1) whole meals or protein-isolates from either soy, canola,or castor that are extracted of their water-soluble polypeptidecomponents at or near pH-neutral conditions; (2) whole meals orprotein-isolates from soy, canola or castor that are subjected to basecatalyzed hydrolysis followed by acid addition and subsequent extractionof water-soluble polypeptide components; (3) whole meals orprotein-isolates from soy, canola or castor that are subjected to acidcatalyzed hydrolysis followed by base addition and subsequent extractionof their water-soluble polypeptide components; (4) whole meals orprotein-isolates from soy, castor, or canola that are subjected tocombinations of base catalyzed hydrolysis with enzyme digestion followedby acid addition and subsequent extraction of water-soluble polypeptidecomponents.

It is understood that the stabilization of an oil-in-water orwater-in-oil emulsion/dispersion depends on several factors, includingbut not limited to the presence or absence of a stabilizing entity suchas a surfactant or a dispersant; the nature of the oil (i.e., itspolarity, hydrophilicity, hydrophobicity, solubility parameter, etc.);the nature of the surfactant or dispersant (i.e., HLB value, chargecharacteristics, molecular weight, water solubility, oil solubility,etc.); the ionic strength of the water-phase; the presence or absence ofadditives and impurities in either the oil or water phases; theconcentration of the oil (i.e., its weight percent in water); and theconcentration of the stabilizing entity. It is further understood thatthe efficiency of a stabilizing entity (a “stabilizing entity” being adispersant, an emulsifier, a surfactant, or thewater-insoluble/water-dispersible polypeptide composition of the presentinvention) is often judged according to its ability stabilize anemulsion for some specified period of time (i.e., to prevent themacroscopic phase separation of immiscible oil and water componentsunder shear or under static conditions).

In order to further demonstrate the generality of this finding, severaloil-in-water dispersions were prepared with awater-insoluble/water-dispersible polypeptide composition that wasisolated from a digested castor protein. Thewater-insoluble/water-dispersible polypeptide fraction was isolated as apaste-like dispersion in water. The paste was diluted with water to 16%solids, and separately to 14% solids. In the next step, 3-gram aliquotsof each paste were separately weighed into 15 mL plastic beakers. Next,aliquots of the oils shown in Table 3 were separately added toindividual paste aliquots at a ratio of 1 part oil to 1 part solidwater-insoluble/water-dispersible polypeptide composition on a weightbasis (20 mixtures in total). The mixtures were stirred by hand with aspatula, and were observed to form homogenous creams. The creamsremained homogeneous with no visible signs of macroscopic phaseseparation for prolonged periods of time after mixing including periodsranging from 1 minute after mixing, 5 minutes after mixing, 10 minutesafter mixing, 15 minutes after mixing, 30 minutes after mixing, 1 hourafter mixing, and 2 hours after mixing. By contrast, the analogouswater-soluble extract from the digested castor was incapable ofstabilizing dispersions of the oils in water.

TABLE 3 Oil Type Source PMDI Rubinate-M from Huntsman CorporationMineral oil Drakeol 35 from Penreco Soybean oil RBD from ADM ProcessingCo. Motor oil Castrol Syntec, 5W-50 Castor oil Pale Pressed Castor Oilfrom Alnor Oil Company, Inc. Dibutyl Phthalate 99% from Acros Epoxidizedsoybean oil From Aldrich Caprylic triglyceride Neobee M-5 from StepanCo. Eucalyptus oil From Aromas Unlimited Tributyl o-acetylcitrate 98%from Aldrich

Protein compositions not enriched for thewater-insoluble/water-dispersible fractions are unable to disperse oils.For example, a 16% solids dispersion of soy protein isolate, Lot 5-81,(Soy protein isolate SOLPRO 958® Solbar Industries Ltd, POB 2230, Ashdod77121, Israel; protein content approximately 90%) was prepared by adding32 grams of soy protein isolate to 168 grams of water at a pH ofapproximately 4 to 6 (JM-570-1). Seven 10 gram aliquots of JM-570-1 wereweighed into 20 mL disposable beakers. A 10 gram aliquot contained 1.6grams of soy protein isolate and 8.4 grams of water. Seven differentoils (namely, PMDI, mineral oil, soybean oil, motor oil, castor oil,dibutyl phthalate and epoxidized soybean oil) were added separately at aw/w ratio of 1 part oil to 1 part protein solids (1.6 grams oil wasadded to each 10 gram aliquot). The mixtures were stirred by hand with aspatula. None of the oils was observed to be dispersible in the 16%solids dispersion of the soy protein isolate.

Example 5: Physical Characterization by Gravimetric Analysis, FTIRSpectroscopy, and Oil-Dispersing Capacity of Ground Canola Meal,Water-Insoluble/Water-Dispersible Protein Fraction Extracted from GroundCanola Meal, and Water-Soluble Protein Fraction Extracted from GroundCanola Meal

Ground canola meal, a water-insoluble/water-dispersible protein fractionthat was extracted from ground canola meal, and a water-soluble proteinfraction that was extracted from ground canola meal were subjected tophysical characterization by gravimetric analysis, FTIR Spectroscopy,and ability to disperse oil. Experimental procedures and results areprovided below.

General Experimental Procedure:

Water-insoluble/water-dispersible protein fraction and water-solubleprotein fraction were isolated from ground canola meal using theisolation method described in Procedure F of Example 1. FTIR spectrawere obtained using solid state FTIR procedures outlined in Part-III ofExample 1. Ability of the ground plant meal and ability of theindividual protein fractions (or a mixture of individual proteinfractions) to disperse PMDI in water was tested using proceduresdescribed in Part-II of Example 1.

Gravimetric Solids Analysis:

After washing and supernatant decanting (3 cycles per the protocol inProcedure F of Example 1), the resulting slurry ofwater-insoluble/water-dispersible components (ca. 35% oven dried solidsby weight) was gravimetrically adjusted to achieve a dispersioncontaining approximately 26% by weight solids (by adding water asnecessary). The overall yield of water-insoluble/water-dispersiblecomponents was determined to be approximately 55% by weight of thestarting meal weight. Thus, the ground canola meal contained (i)approximately 55% by weight of a water-insoluble/water-dispersibleprotein fraction, and (ii) approximately 45% by weight of awater-soluble fraction.

FTIR Spectroscopic Analysis:

To further characterize extracts from the ground canola meal, solidstate surface ATR FTIR experiments were performed on thewater-insoluble/water-dispersible protein fraction (this sample wascollected after the third wash cycle and was allowed to dry at 23° C.),and on the water-soluble protein fraction (this sample was collectedfrom the clear supernatant after the third wash cycle, and was allowedto dry at 23° C. to yield a transparent amber solid).

FIG. 18 shows the solid state FTIR spectra for thewater-insoluble/water-dispersible protein fraction isolated from canolameal together with the water-soluble protein fraction where the N—Hstretching region has been expanded. This figure shows that thepredominant type of amide in the water-insoluble/water-dispersibleprotein fraction is the secondary main-chain amide as evidenced by thesingle, highly symmetric N—H stretch band centered near 3275 cm⁻¹.Although the water-soluble protein fraction also contains this type ofamide, it contains a significantly higher amount of amine salts (asevidenced by absorption over the region spanning from approximately2670-2750 cm⁻¹) and primary amides as evidenced by the presence of thetwo primary N—H stretching bands at approximately 3200 cm⁻¹ (symmetric)and at approximately 3330 cm⁻¹ (asymmetric), respectively. The spectraalso reveal that both fractions contain the characteristic spectroscopicsignatures of proteins, even though both fractions were isolated fromraw meal (raw meal contains other residual water-soluble andwater-insoluble components such as grain hulls, carbohydrates, sugars,and oils).

Further, as shown in FIG. 19, the amide-I carbonyl absorption band forthe water-insoluble/water-dispersible protein fraction was observed toappear as a predominant component at a wavenumber of approximately 1634cm⁻¹, whereas that of the water-soluble protein fraction was observed toappear as a lower-intensity shoulder at approximately 1650 cm⁻¹. Asdiscussed elsewhere, this feature distinguishes thewater-insoluble/water-dispersible protein fraction from thewater-soluble protein fraction, not only for isolated protein fractionsfrom castor proteins and soy proteins, but for protein-containingfractions that are isolated directly from plant meals like soy meal andcanola meal. Moreover, the amide-II band for thewater-insoluble/water-dispersible protein fraction was observed toappear as a broad band centered at approximately 1530 cm⁻¹, whereas thatof the water-soluble protein fraction was observed to appear atapproximately 1588 cm⁻¹ together with a weak shoulder at approximately1550 cm⁻¹.

Analysis of the Capacity of Ground Plant Meal and Isolated ProteinFractions to Disperse Oil:

A dispersion of 26% (w/w) ground whole canola meal in water was mixedwith PMDI at a 1:1 w/w ratio of PMDI to canola meal solids. The canolameal contained (i) approximately 55% by weightwater-insoluble/water-dispersible protein fraction and (ii)approximately 45% by weight water-soluble protein fraction. Thedispersion of ground whole canola meal formed a stable dispersion, whichremained stable during a 1 hour period of observation with no visualsigns of phase separation.

An aliquot of 26% by weight solids dispersion ofwater-insoluble/water-dispersible protein fraction (obtained from canolaplant meal by washing three times per the protocol described inProcedure F of Example 1) was blended with PMDI at a w/w ratio of 1 partPMDI to 1 part of the water-insoluble/water-dispersible protein fraction(on a w/w PMDI/protein fraction-solids basis). This resulting mixtureformed a stable dispersion, which remained stable during a 1 hour periodof observation with no visible signs of phase separation.

The water-soluble protein fraction (obtained by extracting the canolameal and drying the supernatant after centrifuging) was dissolved inwater to yield a 26% (w/w) solids solution. When PMDI was added to thissolution (at a 1:1 weight ratio of PMDI to water-soluble proteinfraction solid material), the resulting mixture was unstable, and itphase separated immediately after mixing.

The results above illustrate that water-emulsified PMDI-containingadhesive compositions can be prepared usingwater-insoluble/water-dispersible protein fraction obtained from groundplant meal. In addition, the results above illustrate thatwater-emulsified PMDI-containing adhesive can be prepared using groundplant meal compositions (that contain a sufficient amount ofwater-insoluble/water-dispersible protein fraction; it is understoodthat the ground plant meal composition also comprises some water-solubleprotein fraction). Although the water-soluble protein fraction did notfacilitate dispersion by itself in these experiments, the dispersion ofPMDI (and other oils) is understood to be achievable so long as asufficient amount of water-insoluble/water-dispersible protein fractionis present in the adhesive composition (or the ground plant meal used inthe adhesive composition).

To further illustrate the oil-dispersing ability of mixtures containinga sufficient amount of water-insoluble/water-dispersible proteinfraction, the oil-dispersing characteristics of a meal containing alarge amount of water-insoluble/water-dispersible protein fraction wascompared to the oil-dispersing characteristics of a commerciallyavailable soy-flour product containing a relatively small amount ofwater-insoluble/water-dispersible protein fraction. The commerciallyavailable soy-flour product used was Prolia PDI-90, which is a de-fattedsoy flour obtained from Cargill).

As is understood, various commercially available derivatives from plantmeals are themselves solvent-extracted (e.g., soy flour), which resultsin the removal of a substantial amount of thewater-insoluble/water-dispersible protein fraction. Such compositionshave not been found to facilitate dispersion of oil, and, thus, are lessdesirable for use in making an adhesive. For example, when PMDI wasadded to a 26% by weight solids dispersion of soy flour in water at a1/1 (w/w) of soy flour/PMDI, the PMDI was observed to immediately phaseseparate from the mixture. By contrast, soy meal was used under similarconditions in Example 1 produced a stable dispersion.

When soy flour was extracted using procedures discussed herein, theisolated water-insoluble/water-dispersible protein fraction was capableof dispersing PMDI in water. However, this fraction was gravimetricallydetermined to comprise only approximately 10% by weight of the startingsoy flour mixture. Thus, the component needed for oil dispersion waspresent in the starting soy flour, but its effective concentration wastoo low for the soy flour disperse PMDI in water. FTIR spectra for theisolated water-insoluble/water-dispersible protein fraction andwater-soluble protein fraction extracted from soy flour are provided inFIG. 20.

In contrast to soy flour, the water-insoluble/water-dispersible proteinfraction is a major component in soy meal (at a level of approximately50% by weight), thus rendering the soy meal an effective dispersingagent for PMDI in water. Upon isolation, thewater-insoluble/water-dispersible protein fraction extracted from bothsoy meal and soy flour (both of which were able to facilitate thedispersion of PMDI in water) were observed to contain similar spectralfeatures as measured by FTIR. Solid state FTIR of thewater-insoluble/water-dispersible protein fraction obtained from soyflour and soy meal are provided in FIG. 21.

Example 6: Preparation of Films & a Pressure-Sensitive Adhesive Madefrom Combinations of Water-Soluble Protein Fraction, Poly(VinylmethylEther-Co-Maleic Anhydride) and Optionally Glycerin

Films and a pressure-sensitive adhesive were made from combinations ofwater-soluble protein fraction, poly(vinylmethyl ether-co-maleicanhydride), and optionally glycerin. In particular, water-solubleprotein fraction from canola meal was reacted with poly(vinylmethylether-co-maleic anhydride) (PMEMA) under basic conditions at a 1/1 w/wratio to yield a gelled network polymer, and separately at a 3/1 w/wratio to yield a pourable water-based dispersion, both of which weredemonstrated to form rigid, water-swellable coatings andpressure-sensitive adhesives when plasticized with glycerin. Theexperimental procedures and results are described below.

Part I: Experimental Procedures

Ground canola meal (20-70 μm) was obtained from Columbia Innovations (adivision of Columbia Forest Products, Inc.); NaOH pellets and glycerinwere obtained from Sigma-Aldrich; and PMEMA was obtained from ISP(Ashland, Inc.) under the trade name Gantrez™ AN-169. Gantrez™ AN-169 isthe tradename for poly(methyl vinyl ether-co-maleic anhydride) havingCAS Reg. No. 9011-16-9 and characterized by a viscosity of 85 centipoiseat 25° C., a nominal molecular weight of 1.98×10⁶ g/mol, a Tg of 154°C., and a specific gravity of 1.017 at a temperature in the range of22-25° C.

The ground canola meal was fractionated to yield a water-soluble proteinfraction (WS fraction) based on procedures described InternationalPatent Application Publication No. WO 2010/102284 and U.S. PatentApplication Publication Nos. 2010/0310877 and 2011/0311833. The meal wasdispersed in distilled water at a concentration of 15% w/w to yield amildly acidic dispersion (pH=5-6), and the resulting slurry wascentrifuged at 3,400 rpm for a period of approximately 35 minutes. Thesupernatant (WS-1), which contained the mildly acidic water-solubleprotein fraction (a cloudy yellowish emulsion; 4.23% solids by weight;pH ca. 5), was decanted from the remaining water-insoluble sediment forlater use. Under these conditions, polypeptide chain ends and side chainresidues (e.g., primary amines, carboxylic acids, lysine residues, andother residues specific to canola protein isolates) tend to beprotonated. See, for example, International Patent ApplicationPublication No. WO 2010/102284 and Canola Meal Feed Industry Guide;Newkirk, R., Ed.; Canadian International Grains Institute, CanolaCouncil of Canada: Winnipeg, 2009, 4^(th) Edition, 2009, p. 10. Analiquot of the WS-1 emulsion was clarified by adding an aqueous 3.65Molal NaOH solution to an endpoint concentration of 0.18 Molal (pH ca.12-13) to yield a yellow solution (WS-2) containing 4% solids by weight.

In a separate step, PMEMA was dissolved in distilled water to yield aclear 4.06% (w/w) aqueous solution of the partially hydrolyzed form ofthe copolymer (PMEMA-mixed acid/anhydride; pH=5-6). An aliquot of thissolution was then partially neutralized to yield the PMEMA-Na salt byadding aqueous 3.65 Molal NaOH to an endpoint concentration of 0.18Molal. Water-based dispersions containing the water-soluble protein andthe PMEMA copolymer (Table 1) were prepared as follows: 1) the WS-1protein emulsion was extracted as noted above; 2) the WS-1 emulsion wasoptionally mixed with aqueous NaOH to form a solution; and 3) theprotein emulsion, or optionally the protein solution (with NaOH) wasmixed with either neat PMEMA (solid powder) or with the PMEMA-mixedacid/anhydride solution. A plasticized composition was also prepared byadding glycerin to the dispersion (Sample E=Sample D+250 phr glycerin).

The starting components and reaction products were dried on glass slidesfor a period of 1-hour at 100° C. for subsequent solid state FTIRanalyses.

TABLE 1 REACTION CONDITIONS AND COMPOSITIONS OF DISPERSIONS Ratio ofWater- Concentration Percent Total Non- Soluble Protein of volatileSample Fraction/PMEMA NaOH Components in Id. (w/w) (Molal) pH Water(w/w) A 1/1 0 5-6 8.36 B 1/1 0.5  9-10 8.73 C 3/1 0 5-6 4.18 D 3/1 0.147-8 4.65 E 3/1 0.14 7-8 13.57

Solid state spectra were acquired by using a Bruker Alpha FTIRspectrometer equipped with a diamond ATR cell (by signal averaging 24scans at 4 cm⁻¹ resolution using an ambient atmosphere backgroundspectrum as the reference). Composite overlay spectra of the carbonylamide and N—H bending regions (ca. 1900-1000 cm⁻¹) were generated forcomparative analyses, and vertical baseline shifting was applied asnecessary. Subtraction spectra were generated to test for the presenceof new absorption bands in the 1/1 WS/PMEMA-mixed acid/anhydride product(Sample A), and in the 1/1 WS/PMEMA-Na salt product (Sample B). Thespectra were generated by subtracting the absorbance spectrum of WS-2from that of the 1/1 WS/PMEMA-Na spectrum, and by subtracting theabsorbance spectrum of WS-1 from that of the 1/1 WS/PMEMA-mixedacid/anhydride spectrum (using factors of 0.41 and 0.5 respectively,which were sufficient to remove the spectral contribution of thestarting protein as indicated by the disappearance of protein-specificbands at 1012 cm⁻¹ and 1654 cm⁻¹).

Spectral band assignments for the PMEMA-mixed acid/anhydride, thePMEMA-Na salt, the WS proteins, and the subtraction-resolved productswere determined from literature references. See, for example, Vandamme,K. et al. European Journal of Pharmaceutics and Biopharmaceutics 2011,79, 392-398; Barth, A. Progress in Biophysics & Molecular Biology 2000,74, 141-173; Lu, Y.; Miller, J. D. Journal of Colloid and InterfaceScience 2002, 256, 41-52; and Colthup, N. B.; Daly, L. H.; Wiberley, S.E. Introduction to Infrared and Raman Spectroscopy, 3^(rd) ed.; AcademicPress: Boston, 1990.

Part II—Results & Discussion

Primary amines in the water-soluble protein fraction can be reacted withfunctionalized copolymers (e.g., maleic anhydride copolymers, epoxies,acid copolymers, etc.) to form water-borne solutions and dispersions foruse as pressure-sensitive adhesives. The water-soluble protein fractioncontains a higher concentration of primary amines thanwater-insoluble/water-dispersible protein fraction, according to NMR andFTIR studies. See, for example, International Patent ApplicationPublication No. WO 2010/102284 and U.S. Patent Application PublicationNo. 2011/0311833.

FTIR analysis was performed on Samples A and B generated in Part I aboveto analyze the reaction product. FTIR subtraction spectra (FIG. 22)revealed the presence of two new absorption bands (centered at 1481 cm⁻¹and between 1339-1361 cm⁻¹) in the 1/1 WS/PMEMA-Na salt reaction product(Sample B) that were not present in the analogous material made undermildly acidic conditions (Sample A). This result indicates that theprotein-PMEMA reaction was favored under basic conditions (i.e., underconditions favoring the formation of free, non-protonated amines).Similar findings were reported in studies detailing the use of maleicanhydride as a blocking agent for lysine residues in chymotrypsinogen,where the amine-anhydride reaction was observed to reach 90% conversionat pH=9 and less than 10% conversion at pH<6. See, for example, Butler,P. J. G. et al. in Biochem. J. 1969, 112, 679-689.

Evidence for water-soluble-amine deprotonation was obtained by comparingFTIR spectra for the WS-1 and WS-2 fractions (cast from mildly acidicand basic solutions, respectively). The spectra revealed the presence oftwo dominant absorption bands, one of which was consistent withamide-carbonyl stretching, and the other with amide C—NH vibration(combination C—N stretching and N—H bending). Under basic conditions(i.e., WS-2), the two bands were observed to shift towards higherwavenumbers (i.e., from 1617 cm⁻¹ to 1654 cm⁻¹, and from 1540 cm⁻¹ to1573 cm⁻¹). In addition, a weak carbonyl band that was present in theWS-1 spectrum (shoulder at ca. 1710-1720 cm⁻¹) was observed to disappearin the WS-2 spectrum.

The above observations are consistent with the deprotonation of anα-amido acid to yield free amines and carboxylate salts. See, forexample, Colthup, N. B. et al. in Introduction to Infrared and RamanSpectroscopy, 3^(rd) ed.; Academic Press: Boston, 1990. In turn, thedeprotonation of the WS protein chain ends and side-chain residues leadsto the availability of primary amines which can participate insolution-phase amine acylation reactions with anhydride-functionalizedpolymers like PMEMA. See, for example, Schmidt, U. et al. in J. Appl.Polym. Sci. 2003, 87, 1255-1266. See, for example, Zhao, M. et al. in J.Am. Chem. Soc., 1999, 121 (5), 923-930.

Upon subtracting the protein spectral contribution from the 1/1WS/PMEMA-Na salt reaction product, three of the remaining bands werecoincident with those of neat PMEMA in the mixed acid/anhydride form(1710 cm⁻¹, 1440 cm⁻¹, and 1180 cm⁻¹), and one was coincident with neatPMEMA in the Na-salt form (1557 cm⁻¹). The presence of these bands incombination with the new bands centered at 1481 cm⁻¹ and between1339-1361 cm⁻¹ is suggestive of a reaction product (Scheme 1 below)composed of a combination of free acid groups, sodium carboxylate salts,and protein-PMEMA bonds.

The positions of the new bands are too low in wavenumber to beconsistent with the formation of cyclic imides. Instead, they are morelikely to be consistent with the N—H bending and C—N stretchingvibrations for cis-constrained amide structures. See, for example,Colthup, N. B. et al. in Introduction to Infrared and RamanSpectroscopy, 3^(rd) ed.; Academic Press: Boston, 1990. This possibilityis plausible given that the reaction between the protein amines (e.g.,lysine) with the PMEMA under basic conditions would result in an amidethat is directly adjacent to a free carboxylic acid group. Crosslinkingreactions are also plausible given that the water-soluble proteins arelikely to contain more than one amine equivalent per chain. This issupported by the observation that the 1/1 WS/PMEMA-Na salt formed astable gel when reacted under basic conditions, and was also insolublein water after drying (Table 2).

TABLE 2 REACTION PRODUCT QUALITATIVE OBSERVATIONS Sample State ofQualitative Characteristics of Films Id. Dispersion in Water Dried OneHour at 100° C. A & C Unstable yellow Rigid, clear heterogeneous/grainyyellow precipitate with film; swells and disintegrates in water settling(pourable) B Stable, high Rigid, homogeneous, transparent yellowviscosity yellow gel film; swells in water (not soluble) (not pourable)D Stable low viscosity Rigid, homogeneous, transparent yellow dispersionfilm; swells in water (partially soluble) E Stable low viscosityTransparent, low Tg, tacky film; swells dispersion in water (partiallysoluble)

Another observation is that the most stable gels and emulsions werethose that were formed under basic conditions.

In summary, water-soluble protein fraction isolated from meals likecanola can be used in combination with functionalized copolymers (e.g.,anhydride copolymers) produce reactive water-based gels and emulsions,which in turn, can be used to create and coatings and adhesives. Theexamples presented here illustrate how it is possible to utilize proteinfractions from a low-cost organic meal to produce useful materials andproducts for the chemical industry.

Example 7: Preparation of Adhesives Containing Water-Soluble ProteinFraction Optionally with Plasticizer and/or Anhydride Compound

Adhesives containing water-soluble protein fraction were prepared andcharacterized. The adhesives optionally contained a plasticizer and/oranhydride compound. Experimental procedures and results are describedbelow.

Part I—Preparation of Water-Soluble Protein Fraction from Canola Meal

Multiple samples of water-soluble protein fraction were isolated fromcanola meal following the procedures described in Table 1 below.Distilled water used in the experiments had a pH of approximately 5-6.Physical characterization data for the samples of water-soluble proteinfraction are described in Table 2 below.

TABLE 1 ISOLATION OF WATER-SOLUBLE PROTEIN FRACTION Sample No.Experimental Procedure JM-1003 525 grams of distilled water was weighedinto a one quart, lined paint can. The can was placed into a heatingmantle, manufactured by Glas-Col Apparatus Company, Terre Haute, IN. Theheating mantle was combined with a Stir-Pak Laboratory Stirrer obtainedfrom Cole Parmer Corporation. 225 grams of ground Cargill canola mealwas added slowly to the water while stirring resulting in a 30% solidsdispersion of canola meal in water. After the addition of the canolameal the temperature was increased and maintained in the temperaturerange 40° C. to 50° C. for 1.5 hours. The sample was taken out of theheating mantle, capped and allowed to cool on the bench top overnight.500 grams of the cooled canola dispersion was diluted with 500 grams ofdistilled water to reduce the solids content to 15%. This was done toreduce viscosity and to facilitate centrifugation of the dispersion toseparate out the solids. The 15% solids dispersion was centrifuged, 6samples at a time, using 15 ml conical centrifuge tubes and a ColeParmer centrifuge operating at 3400 rpm for approximately 35 minutes.The supernatant and the solids were collected in separate containers.This process was repeated until all of the dispersion was centrifuged.The percent solids, of the collected supernatant, were measured usingoven drying and gravimetric methods and found to be 4.23%. JM-1032-1Under ambient laboratory conditions, 331.2 grams of distilled water wasadded to a 500 ml high-density polyethylene bottle to which 8.8 grams ofa 3.65 Molal solution of sodium hydroxide was added to yield 340 gramsof a solution (effectively 0.082 Molal) having a pH of 12.88. 60 gramsof ground Cargill canola meal was then added to the bottle resulting ina total mass of 400 grams. The pH of the dispersion was measuredimmediately after mixing and found to be 10.02. The sample was mixedovernight by rolling the bottle on a rolling mixer. The pH was measuredafter 16 hours of mixing and found to be 9.33. The plastic bottle wasput into a Beckman CS-6 Centrifuge and spun at 3150 rpm for 30 minutes.The supernatant and the solids were collected in separate containers.The percent solids, of the collected supernatant, were measured usingoven drying and gravimetric methods and found to be 5.99%. JM-1032-2Under ambient laboratory conditions, 340 grams of a 1.0 Molal calciumhydroxide solution, pH = 12.94, was added to a 500 ml high-densitypolyethylene bottle. 60 grams of ground Cargill canola meal was thenadded to the bottle resulting in a total mass of 400 grams. The pH ofthe dispersion was measured immediately after mixing and found to be12.81. The sample was mixed overnight by rolling the bottle on a rollingmixer. The pH was measured after 16 hours of mixing and was found to12.84. The plastic bottle was put into a Beckman CS-6 Centrifuge andspun at 3150 rpm for 30 minutes. The supernatant and the solids werecollected in separate containers. The percent solids, of the collectedsupernatant, were measured using oven drying and gravimetric methods andfound to be 5.36%. JM-1032-3 Under ambient laboratory conditions, 340grams of distilled water, pH = 5.50, was added to a 500 ml high-densitypolyethylene bottle. 60 grams of ground Cargill canola meal was thenadded to the bottle resulting in a total mass of 400 grams. The pH ofthe dispersion was measured immediately after mixing and found to be5.85. The sample was mixed overnight by rolling the bottle on a rollingmixer. The pH was measured after 16 hours of mixing and found to 6.01.The plastic bottle was put into a Beckman CS-6 Centrifuge and spun at3150 rpm for 30 minutes. The supernatant and the solids were collectedin separate containers. The percent solids, of the collectedsupernatant, were measured using oven drying and gravimetric methods andfound to be 3.78%. JM-1039-1 Under ambient laboratory conditions, 340grams of a 0.053 Molal sodium hydroxide solution was added to a 500 mlhigh- density polyethylene bottle. 60 grams of ground Cargill canolameal was then added to the bottle resulting in a total mass of 400grams. The pH of the dispersion was measured immediately after mixingand found to be 8.76. The sample was mixed overnight by rolling thebottle on a rolling mixer. The pH was measured after 16 hours of mixingand found to 8.44. The plastic bottle was put into a Beckman CS-6Centrifuge and spun at 3150 rpm for 30 minutes. The supernatant and thesolids were collected in separate containers. The percent solids, of thecollected supernatant, were measured using oven drying and gravimetricmethods and found to be 4.35%. JM-1039-2 Under ambient laboratoryconditions, 340 grams of a 0.032 Molal sodium hydroxide solution wasadded to a 500 ml high- density polyethylene bottle. 60 grams of groundCargill canola meal was then added to the bottle resulting in a totalmass of 400 grams. The pH of the dispersion was measured immediatelyafter mixing and found to be 7.77. The sample was mixed overnight byrolling the bottle on a rolling mixer. The pH was measured after 16hours of mixing and found to 7.42. The plastic bottle was put into aBeckman CS-6 Centrifuge and spun at 3150 rpm for 30 minutes. Thesupernatant and the solids were collected in separate containers. Thepercent solids, of the collected supernatant, were measured using ovendrying and gravimetric methods and found to be 4.31%. JM-1042-1 Underambient laboratory conditions, 340 grams of a 0.042 Molal calciumhydroxide solution was added to a 500 ml high-density polyethylenebottle. 60 grams of ground Cargill canola meal was then added to thebottle resulting in a total mass of 400 grams. The pH of the dispersionwas measured immediately after mixing and found to be 9.7. The samplewas mixed overnight by rolling the bottle on a rolling mixer. The pH wasmeasured after 16 hours of mixing and found to 9.01. The plastic bottlewas put into a Beckman CS-6 Centrifuge and spun at 3150 rpm for 30minutes. The supernatant and the solids were collected in separatecontainers. The percent solids, of the collected supernatant, weremeasured using oven drying and gravimetric methods and found to be 3.88%JM-1042-2 Under ambient laboratory conditions, 340 grams of a 0.025Molal calcium hydroxide solution was added to a 500 ml high-densitypolyethylene bottle. 60 grams of ground Cargill canola meal was thenadded to the bottle resulting in a total mass of 400 grams. The pH ofthe dispersion was measured immediately after mixing and found to be8.7. The sample was mixed overnight by rolling the bottle on a rollingmixer. The pH was measured after 16 hours of mixing and found to 8.04.The plastic bottle was put into a Beckman CS-6 Centrifuge and spun at3150 rpm for 30 minutes. The supernatant and the solids were collectedin separate containers. The percent solids, of the collectedsupernatant, were measured using oven drying and gravimetric methods andfound to be 3.79%. JM-1042-3 Under ambient laboratory conditions, 340grams of a 0.013 Molal calcium hydroxide solution was added to a 500 mlhigh-density polyethylene bottle. 60 grams of ground Cargill canola mealwas then added to the bottle resulting in a total mass of 400 grams. ThepH of the dispersion was measured immediately after mixing and found tobe 7.18. The sample was mixed overnight by rolling the bottle on arolling mixer. The pH was measured after 16 hours of mixing and found to6.88. The plastic bottle was put into a Beckman CS-6 Centrifuge and spunat 3150 rpm for 30 minutes. The supernatant and the solids werecollected in separate containers. The percent solids, of the collectedsupernatant, were measured using oven drying and gravimetric methods andfound to be 3.75%.

TABLE 2 WATER-SOLUBLE PROTEIN FRACTION ISOLATED FROM CANOLA MEAL pH ofStarting pH of Base Solution Supernatant Percent Concentration (beforeExtract (after Solids in Sample (moles/Kg adding separation ExtractAppearance of No. Base water) meal) from meal) (%) Extract JM1003 None 05 to 6 5 to 6 4.23 Yellow emulsion JM1032 NaOH 0.082 12.88 9.18 5.99Amber −1 translucent solution with dispersible sediment JM1032 Ca(OH)₂1.0 12.94 12.48 5.36 Dark green −2 (partially translucent soluble)solution with dispersible sediment JM1032 None 0 5.5 5.92 3.78 Amber −3translucent solution with dispersible sediment JM1039 NaOH 0.053 12.38.32 4.35 Amber −1 translucent solution with dispersible sediment JM1039NaOH 0.032 12.3 7.35 4.31 Amber −2 translucent solution with dispersiblesediment JM1042 Ca(OH)₂ 0.042 12.57 8.95 3.88 Amber −1 translucentsolution with dispersible sediment JM1042 Ca(OH)₂ 0.025 12.63 8.0 3.79Amber −2 translucent solution with dispersible sediment JM1042 Ca(OH)₂0.013 12.6 6.87 3.75 Amber −3 translucent solution with dispersiblesedimentPart II: Preparation of Adhesives Containing Water-Soluble Protein-BasedExtracts

In each of the following experiments, the water-based supernatants fromPart I above were shaken thoroughly before use to re-disperseparticulates that may have settled during storage. The water-solubleextracts were cast on glass slides and were dried at 100° C. for 1 hour.The resulting films were rigid, and were qualitatively observed toexhibit a high degree of adhesion to the glass slides (the films couldnot be removed unless they were scraped with a razor blade). Given thatthe films were not tacky, pressure activated adhesion was not possibleat 25° C. For example, when 22 lb. (83 g/m²) white letter paper waspressed against the coated slides, the paper did not stick, and fell offof the coated glass surface. The qualitative characteristics of thefilms are provided in Table 3.

TABLE 3 QUALITATIVE CHARACTERISTICS OF RIGID (NON-TACKY) ADHESIVES ONGLASS (CONTAINING WATER-SOLUBLE PROTEIN-BASED EXTRACTS FROM CANOLA MEAL)Qualitative Pressure Adhesion Activated Sample Strength to AdhesionQualitative No. Color/clarity Glass to Paper Properties JM1003yellow/transparent high none Rigid, brittle, no tack JM1032-1yellow/transparent high none Rigid, brittle, no tack JM1032-2yellow/transparent high none Rigid, brittle, no tack JM1032-3yellow/transparent high none Rigid, brittle, no tack JM1039-1yellow/transparent high none Rigid, brittle, no tack JM1039-2yellow/transparent high none Rigid, brittle, no tack JM1042-1yellow/transparent high none Rigid, brittle, no tack JM1042-2yellow/transparent high none Rigid, brittle, no tack JM1042-3yellow/transparent high none Rigid, brittle, no tackPart III: Preparation of Protein-Based Adhesives with Plasticizer(Glycerin)

In each of the following experiments, the water-based supernatants fromPart I above were shaken thoroughly before use to re-disperseparticulates that may have settled during storage. In addition, theformulated adhesives (with glycerin) were also shaken prior to use forthe purpose of re-dispersing particulates that may have settled. Thewater-soluble protein fraction was blended with glycerin for the purposeof plasticizing the materials (i.e., to reduce the glass transitiontemperature for the purpose of increasing tack). The adhesives were caston glass slides and were dried at 100° C. for 1 hour to yieldtransparent yellow films (wet compositions are provided in Table 4, andsolid compositions are given in Table 5). The coated glass specimenswere pressed together by hand with pre-cut paper coupons, and wereallowed to set for approximately 18 hours before being subjected toqualitative peel delamination testing. The paper coupons were thenpartially peeled from the glass to evaluate relative peelcharacteristics. The samples were then re-adhered by hand, and weresubjected to second peel tests.

The results in Table 6 describe the samples after being subjected to thepeel tests. All the adhesives were observed to bond with paper and withglass. However, the adhesives were cohesively weak, and were observed tocohesively fail upon peeling the specimens. Moreover, the qualitativecohesive strength of the adhesives was observed to decrease withincreasing levels of glycerin plasticizer. Tackiness of the adhesive wasobserved to increase with increasing glycerin content.

After the first and second peel tests were complete, the peeledspecimens were once again re-adhered for a 3^(rd) time, and were thenre-evaluated 5 days later. Several of the specimens that had previouslydisplayed poor paper-to-glass adhesion strength (see Table 6) wereobserved to become cohesively stronger, and were observed to invokedpaper cohesive tear upon delamination (samples TP17-9, TP17-10, TP17-11,TP17-14, TP17-15, and TP-16). Thus, the adhesive materials havestrengthened over time.

TABLE 4 WET COMPOSITIONS OF PLASTICIZED PROTEIN-BASED ADHESIVES Water-Percent Soluble Protein Percent Adhesive Protein Counter- Percent MealPercent Non- Sample Fraction ion Water Extract Glycerin volatiles No.Sample No. Type (%) (%) (%) % TP17-1 JM1032-1 Na 82.37 5.25 12.38 17.63TP17-2 JM1032-2 Ca 83.79 4.75 11.46 16.21 TP17-3 JM1032-3 None 87.693.45 8.86 12.31 TP17-4 JM1039-1 Na 85.49 3.89 10.62 14.51 TP17-5JM1039-2 Na 84.48 3.81 11.72 15.52 TP17-6 JM1042-1 Ca 86.95 3.51 9.5413.05 TP17-7 JM1042-2 Ca 86.12 3.39 10.48 13.88 TP17-8 JM1042-3 Ca 88.153.43 8.42 11.85 TP17-9 JM1032-1 Na 83.09 5.29 11.61 16.91 TP17-10JM1032-2 Ca 85.59 4.85 9.56 14.41 TP17-11 JM1032-3 None 89.30 3.51 7.1910.70 TP17-12 JM1039-1 Na 88.21 4.01 7.78 11.79 TP17-13 JM1039-2 Na88.28 3.98 7.75 11.72 TP17-14 JM1042-1 Ca 88.89 3.59 7.52 11.11 TP17-15JM1042-2 Ca 88.43 3.48 8.09 11.57 TP17-16 JM1042-3 Ca 89.28 3.48 7.2410.72

TABLE 5 DRY COMPOSITIONS OF PLASTICIZED PROTEIN-BASED ADHESIVES Water-Soluble Percent Phr Protein Water- Glycerin Adhesive Fraction SolublePercent (parts per Sample Sample Counter- Protein Glycerin hundred No.No. ion Type Fraction (%) (%) resin) TP17-1 JM1032-1 Na 29.77 70.23 236TP17-2 JM1032-2 Ca 29.28 70.72 242 TP17-3 JM1032-3 None 28.00 72.00 257TP17-4 JM1039-1 Na 26.80 73.20 273 TP17-5 JM1039-2 Na 24.51 75.49 308TP17-6 JM1042-1 Ca 26.89 73.11 272 TP17-7 JM1042-2 Ca 24.45 75.55 309TP17-8 JM1042-3 Ca 28.98 71.02 245 TP17-9 JM1032-1 Na 31.31 68.69 219TP17-10 JM1032-2 Ca 33.65 66.35 197 TP17-11 JM1032-3 None 32.78 67.22205 TP17-12 JM1039-1 Na 34.03 65.97 194 TP17-13 JM1039-2 Na 33.92 66.08195 TP17-14 JM1042-1 Ca 32.31 67.69 210 TP17-15 JM1042-2 Ca 30.10 69.90232 TP17-16 JM1042-3 Ca 32.46 67.54 208

TABLE 6 QUALITATIVE CHARACTERISTICS OF PLASTICIZED PROTEIN- BASED FILMS,AND QUALITATIVE CHARACTERISTICS OF PAPER-TO-GLASS PEEL SPECIMENS AFTERPEEL TESTING Glass-to Adhesive Paper Qualitative Tack of Re- SampleColor/ Degree of Cohesive Stiffness of Exposed adhesion No. ClarityDelamination Failure Adhesive Adhesive After Peel TP17-1 Transparent/None, adhesive None, adhesive Low stiffness Tacky & Same Yellow remainedremained weak result as adhered to glass adhered to first peel &cohesively paper & test failed cohesively failed TP17-2 Transparent/None, adhesive None, adhesive Low stiffness Tacky & Same Yellow remainedremained weak result as adhered to glass adhered to first peel &cohesively paper & test failed cohesively failed TP17-3 Transparent/None, adhesive None, adhesive Low stiffness Tacky & Same Yellow remainedremained weak result as adhered to glass adhered to first peel &cohesively paper & test failed cohesively failed TP17-4 Transparent/None, adhesive None, adhesive Low stiffness Tacky & Same Yellow remainedremained weak result as adhered to glass adhered to first peel &cohesively paper & test failed cohesively failed TP17-5 Transparent/None, adhesive None, adhesive Low stiffness Tacky & Same Yellow remainedremained weak result as adhered to glass adhered to first peel &cohesively paper & test failed cohesively failed TP17-6 Transparent/None, adhesive None, adhesive Low stiffness Tacky & Same Yellow remainedremained weak result as adhered to glass adhered to first peel &cohesively paper & test failed cohesively failed TP17-7 Transparent/None, adhesive None, adhesive Low stiffness Tacky & Same Yellow remainedremained weak result as adhered to glass adhered to first peel &cohesively paper & test failed cohesively failed TP17-8 Transparent/None, adhesive None, adhesive Low stiffness Tacky & Same Yellow remainedremained weak result as adhered to glass adhered to first peel &cohesively paper & test failed cohesively failed TP17-9 Transparent/None, adhesive None, adhesive Low stiffness Tacky & Same Yellow remainedremained weak result as adhered to glass adhered to first peel &cohesively paper & test failed cohesively failed TP17-10 Transparent/None, adhesive None, adhesive Low stiffness, Tacky & Same Yellowremained remained but > TP17-9 weak result as adhered to glass adheredto first peel & cohesively paper & test failed cohesively failed TP17-11Transparent/ None, adhesive None, adhesive Low stiffness, Tacky & SameYellow remained remained like TP17-10 weak result as adhered to glassadhered to first peel & cohesively paper & test failed cohesively failedTP17-12 Transparent/ None, adhesive None, adhesive Low stiffness, Tacky& Same Yellow remained remained like TP17-10 weak result as adhered toglass adhered to first peel & cohesively paper & test failed cohesivelyfailed TP17-13 Transparent/ None, adhesive None, adhesive Low stiffness,Tacky & Same Yellow remained remained like TP17-10 weak result asadhered to glass adhered to first peel & cohesively paper & test failedcohesively failed TP17-14 Transparent/ None, adhesive None, adhesiveModerate Tacky, Same Yellow remained remained stiffness but less resultas adhered to glass adhered to (highest of tacky first peel & cohesivelypaper & group) than test failed cohesively TP17-13 failed TP17-15Transparent/ None, adhesive None, adhesive Moderate Tacky, Same Yellowremained remained stiffness like like result as adhered to glass adheredto TP17-15 TP17-14 first peel & cohesively paper & test failedcohesively failed TP17-16 Transparent/ None, adhesive None, adhesive Lowstiffness, Tacky & Same yellow remained remained like TP17-10 weakresult as adhered to glass adhered to first peel & cohesively paper &test failed cohesively failedPart IV: Preparation of Water-Soluble Protein Fraction ContainingAdhesives with Plasticizer and Anhydride Polymer

Due to the relatively low cohesive strengths of the adhesives describedin Tables 4 through 6 (Part-III above), a polymer with anhydridefunctionality was incorporated into the formulas for the purpose ofenhancing strength. Given that the water soluble proteins containprimary amines, it follows that the incorporation of an anhydridefunctionalized polymer could lead to chain extension and crosslinking,which in turn would help to enhance cohesive strength. In order toillustrate this, formulations were prepared with similar compositions tothose presented in Tables 4 through 6 (Part-III above), but with oneexception: some of the water soluble protein-based extract was replacedwith Gantrez™ AN-169 (abbreviated as “GAN”). The overall level ofglycerin plasticizer was similar to those that were used in severalformulas from Part-III.

In each of the following experiments, the water-based supernatants fromPart I above were shaken thoroughly before use to re-disperseparticulates that may have settled during storage. Aliquots of theextracts were then mixed with a separate solution of Gantrez AN 169(4.056% w/w in water) using various proportions in conjunction withglycerin to yield the wet adhesive compositions as described in Table 7.The formulated adhesives (containing the reaction products and glycerin)were shaken prior to use for the purpose of re-dispersing particulatesthat may have settled. The wet adhesives were cast on glass slides andwere dried at 100° C. for 1 hour to yield transparent yellow films(solid compositions are given in Table 8). The coated glass specimenswere pressed together by hand with pre-cut paper coupons, and wereallowed to set for approximately 18 hours before being subjected toqualitative peel delamination testing. The paper coupons were thenpartially peeled from the glass to evaluate relative peelcharacteristics. The samples were then re-adhered by hand, and weresubjected to second peel tests.

The results in Table 9 describe the samples after being subjected to thepeel tests. All adhesives were observed to bond paper to glass.Importantly, all of the adhesives were also cohesively stronger thantheir counterparts from Part-III, independent of whether the plasticizerconcentration was higher or lower than that which was used in thecomparative Part-III samples. These results illustrate the benefit offormulating adhesives with reaction products comprised of functionalizedcopolymers (i.e., a maleated copolymer in this case) reacted togetherwith the water-based protein fractions. Adhesives of this type exhibitimproved cohesive strength characteristics, and allow for theformulation of adhesives with characteristics ranging from reversible(e.g., TP18-2) to non-reversible (e.g., TP19-2).

TABLE 7 WET COMPOSITIONS OF PLASTICIZED PROTEIN-BASED ADHESIVES WITH GANWater- Percent Soluble Water Percent Ratio of Protein Soluble GANProtein/ Percent Fraction Counter- Percent Protein Percent Anhydride GANnon- Sample Sample ion Water Fraction Glycerin Polymer Anhydridevolatiles No. No. Type (%) (%) (%) (%) (w/w) (%) TP18-1 JM1032-1 Na⁺84.42 3.67 10.78 1.14 3.23 15.58 TP18-2 JM1032-2 Ca²⁺ 85.50 3.48 10.001.01 3.44 14.50 TP18-3 JM1032-3 None 88.76 2.75 7.69 0.79 3.48 11.24TP18-4 JM1039-1 Na⁺ 86.89 2.98 9.22 0.91 3.29 13.11 TP18-5 JM1039-2 Na⁺87.05 2.97 9.09 0.89 3.33 12.95 TP18-6 JM1042-1 Ca²⁺ 88.07 2.76 8.330.84 3.30 11.93 TP18-7 JM1042-2 Ca²⁺ 88.42 2.72 8.04 0.82 3.34 11.58TP18-8 JM1042-3 Ca²⁺ 89.28 2.71 7.18 0.83 3.26 10.72 TP19-1 JM1042-3Ca²⁺ 89.27 2.71 7.19 0.83 3.25 10.73 TP19-2 JM1042-3 Ca²⁺ 89.38% 3.127.11 0.39 8.04 10.62 TP19-3 JM1042-3 Ca²⁺ 89.35 3.05 7.13 0.47 6.5210.65 (pro- phetic) TP19-4 JM1042-3 Ca²⁺ 89.38 3.19 7.11 0.32 10.0010.62 (pro- phetic)

TABLE 8 DRY COMPOSITIONS OF PLASTICIZED PROTEIN-BASED ADHESIVES WITH GANWater- Phr Soluble Percent Glycerin Protein Protein Percent Protein/(parts Fraction Counter- Meal Percent GAN GAN per Sample Sample ionExtract Glycerin Anhydride Anhydride hundred No. No. Type (%) (%)Polymer (w/w) resin) TP18-1 JM1032-1 Na⁺ 23.53 69.17 7.29 3.23 224TP18-2 JM1032-2 Ca²⁺ 24.03 68.98 6.99 3.44 222 TP18-3 JM1032-3 None24.50 68.47 7.03 3.48 217 TP18-4 JM1039-1 Na⁺ 22.72 70.37 6.91 3.29 238TP18-5 JM1039-2 Na⁺ 22.93 70.18 6.89 3.33 235 TP18-6 JM1042-1 Ca²⁺ 23.1269.87 7.00 3.30 232 TP18-7 JM1042-2 Ca²⁺ 23.52 69.44 7.04 3.34 227TP18-8 JM1042-3 Ca²⁺ 25.29 66.95 7.76 3.26 203 TP19-1 JM1042-3 Ca²⁺25.23 66.99 7.78 3.25 203 TP19-2 JM1042-3 Ca²⁺ 29.41 66.93 3.66 8.04 202TP19-3 JM1042-3 Ca²⁺ 28.65 66.96 4.39 6.52 203 (prophetic) TP19-4JM1042-3 Ca²⁺ 30.04 66.96 3.01 10.00 203 (prophetic)

TABLE 9 QUALITATIVE CHARACTERISTICS OF PLASTICIZED PROTEIN- BASED FILMSWITH GAN, AND QUALITATIVE CHARACTERISTICS OF PAPER- TO-GLASS PEELSPECIMENS AFTER PEEL TESTING Glass-to- Qualitative Adhesive Stiffness &Degree of Paper Cohesive Tack of Re- Sample Color/ Delamin- CohesiveProperties of Exposed adhesion No. Clarity ation Failure AdhesiveAdhesive After Peel TP18-1 Transparent/ None Fibers left on Higher thanmoderate Low Yellow surface of comparable adhesion adhesive formulasTP17-1 due to fiber and TP17-9 on surface TP18-2 Transparent/ None None(paper peels Higher than Low-to Easily peels Yellow cleanly) comparablemoderate and re- formulas TP17-2 adheres and TP17-10 TP18-3 Transparent/None Extreme paper Higher than High tack Non- Yellow tear comparablereversible formulas TP17-3 and TP17-11 TP18-4 Transparent/ None Fibersleft on Higher than Moderate Low Yellow surface of comparable adhesionadhesive formulas TP17-4 due to fiber and TP17-12 on surface TP18-5Transparent/ None Extreme paper Higher than High tack Non- Yellow tearcomparable reversible formulas TP17-5 and TP17-13 TP18-6 Transparent/None Extreme paper Higher than High tack Non- Yellow tear comparablereversible formulas TP17-6 and TP17-14 TP18-7 Transparent/ None Extremepaper Higher than High tack Non- Yellow tear comparable reversibleformulas TP17-7 and TP17-15 TP18-8 Transparent/ None Extreme paperHigher than High tack Non- Yellow tear comparable reversible formulasTP17-8 and TP17-16 TP19-1 Transparent/ None Extreme paper Higher thanHigh tack Non- Yellow tear comparable reversible formulas TP17-8 andTP17-16 TP19-2 Transparent/ None Extreme paper Higher than High tackNon- Yellow tear comparable reversible formulas TP17-8 and TP17-16

Example 8: Preparation of Pressure-Sensitive Adhesive from Water-SolubleProtein Fraction and Anhydride-Functionalized Copolymer

Pressure-sensitive adhesives were prepared that contain ananhydride-functionalized copolymer reacted together with a water-solubleprotein fraction obtained from canola meal in the presence of NaOH. Theresulting adhesives were plasticized with various levels of glycerin toillustrate the varying degrees of tack and stiffness that are possible.Of course, it is understood that other types monomeric and polymericplasticizers, as well as other additives, could also be used inconjunction with the protein-based adhesive.

The adhesives in this example were prepared with the water-solubleprotein fraction JM1003 (4.23% w/w solids) as described in Example 7. Aprotein-based solution (12-1) was prepared by adding 0.73 g of a 3 MolalNaOH solution to 15 g of JM1003 (the final pH was approximately 7). Asecond protein-based solution (12-2) was prepared by adding 0.85 g of a3 Molal NaOH solution to 15 g of JM1003 (the final pH was approximately8).

A separate solution of Gantrez AN 169 (4.056% w/w in water; abbreviatedas “GAN”) was added to aliquots of the 12-1 and 12-2 solutions usingvarious proportions in conjunction with glycerin to yield the wetcompositions as described in Table 1. The adhesives were cast on glassslides and were dried at 100° C. for 1 hour to yield transparent yellowfilms (solid compositions are given in Table 2). The coated glassspecimens were pressed together by hand with paper coupons, and wereallowed to set for approximately 18 hours before being subjected toqualitative peel delamination testing. The paper coupons were thenpartially peeled from the glass to evaluate relative peelcharacteristics. The samples were then re-adhered by hand, and weresubjected to second peel tests.

The results in Table 3 describe the samples after being subjected to thepeel tests. All of the adhesives were observed to bond paper to glass.

After the peel tests were complete, two of the adhesives (samplesTP12-2-3 and TP12-2-4) were observed to completely delaminate from theglass, and the adhesive films remained adhered to the paper. Thesespecimens were separately pressed against paper coupons to yieldpaper-to-adhesive-to-paper laminates. The paper laminates were thenallowed to set for approximately 18 hours and were subsequently peeledapart. The adhesives were qualitatively observed to form strong bondswith the paper, and the paper was observed to cohesively tear in bothcases. These results suggest that the adhesives can be alternativelycast onto releasing substrates (e.g., silicone-coated paper) for thepurpose of preparing transfer pressure-sensitive adhesives for paper(e.g., to form adhesive-backed paper labels).

TABLE 1 WET COMPOSITIONS OF PLASTICIZED WATER-SOLUBLE PROTEIN-CONTAININGADHESIVES Percent Protein Percent Ratio of Water- Meal GAN Protein/Percent Based Counter- Percent Extract + Percent Anhydride GAN Non-Sample Extract ion Water NaOH Glycerin Polymer Anhydride volatiles No.Type Type (%) (%) (%) (%) (w/w) (%) TP12-1- 12-1 Na⁺ 89.87 3.29 5.970.87 3.36/1 10.13 1 TP12-1- 12-1 Na⁺ 88.29 3.23 7.62 0.86 3.36/1 11.71 2TP12-1- 12-1 Na⁺ 85.94 3.14 10.09 0.83 3.36/1 14.06 3 TP12-2- 12-2 Na⁺89.09 3.30 6.75 0.86 3.36/1 10.91 1 TP12-2- 12-2 Na⁺ 88.60 3.28 7.260.85 3.36/1 11.40 2 TP12-2- 12-2 Na⁺ 85.77 3.18 10.23 0.83 3.36/1 14.233 TP12-2- 12-2 Na⁺ 84.54 3.13 11.51 0.81 3.36/1 15.46 4

TABLE 2 DRY COMPOSITIONS OF PLASTICIZED WATER-SOLUBLE PROTEIN-CONTAININGADHESIVES Percent Phr Protein Percent Glycerin Meal GAN Ratio of (partsper Extract + Percent Anhydride Protein/GAN Sample hundred NaOH GlycerinPolymer Anhydride No. resin) (%) (%) (%) (w/w) TP12-1-1 144 32.45 58.948.61 3.36/1 TP12-1-2 187 27.58 65.11 7.31 3.36/1 TP12-1-3 254 22.3571.72 5.93 3.36/1 TP12-2-1 162 30.25 61.88 7.87 3.36/1 TP12-2-2 17628.80 63.71 7.49 3.36/1 TP12-2-3 255 22.32 71.87 5.81 3.36/1 TP12-2-4292 20.26 74.47 5.27 3.36/1

TABLE 3 QUALITATIVE CHARACTERISTICS OF PAPER-TO-GLASS PEEL SPECIMENSAFTER PEEL TESTING. Phr Glass-to- Glycerin Adhesive Paper QualitativeTack of (parts per Sample Color/ Degree of Cohesive Stiffness of ExposedRe-adhesion hundred No. Clarity Delamination Failure Adhesive AdhesiveAfter Peel resin) TP12-1-1 Transparent/ Remained Partial; Highest of Low(due Low (due to 144 yellow adhered paper fibers group to paper paperfibers) near fibers on adhesive surface) surface TP12-1-2 Transparent/80% remained None; <TP12-1-1 moderate Reversible, 187 yellow adhered;some some but lower transfer to adhesive delamination paper (legs)transfer to force paper TP12-1-3 Transparent/ 50% remained NoneLow; >TP12-1-1 Reversible 254 yellow adhered; 50% <TP12-1-2; withsimilar transfer to like TP12-2-2 tack and paper (legs & delaminationfilm-forming) force TP12-2-1 Transparent/ Like TP12-1-2 None LikeModerate Reversible 162 yellow TP12-1-2 with similar tack anddelamination force TP12-2-2 Transparent/ Remained Partial; Like Low (dueLow (due to 176 yellow adhered paper fibers TP12-2-1 to paper paperfibers) near fibers on adhesive surface) surface TP12-2-3 Transparent/Good adhesion None <TP12-2-2 moderate Reversible 255 yellow to glass,but (adhesive with similar slow peel transferred tack and allowed topaper) delamination complete force transfer to paper TP12-2-4Transparent/ Good adhesion None <TP12-2-3 moderate Reversible 292 yellowto glass, but (adhesive with similar slow peel transferred tack andallowed to paper) delamination complete force transfer to paper

Example 9: Preparation of High-Solids Pressure-Sensitive Adhesives fromWater-Soluble Protein Fraction and Anhydride-functionalized Copolymer

High-solids pressure-sensitive adhesives were prepared from ananhydride-functionalized copolymer and water-soluble protein fractionobtained from canola meal. The water-soluble protein fraction wasisolated and spray-dried by CanPro Ingredients, Ltd., Arborfield,Saskatchewan, Canada. The CanPro water-soluble protein fraction wasmixed with water in the presence and absence of base (1-molal Ca(OH)₂)to yield the 50% solids (w/w) mixtures described in Table 1.

TABLE 1 50% (W/W) SOLIDS WATER-SOLUBLE PROTEIN FRACTIONS Weight PercentCanPro Water- Soluble Protein pH After Sample No. Liquid CarrierFraction (%) Mixing JM1072-1 1-molal aqueous Ca(OH)₂ 50 6.14 JM1074-5JM1072-1 [1-molal 50 7.6 aqueous Ca(OH)₂) + 1-molal NaOH solution]JM1074-4 water 50 6.10

The samples from Table 1 were mixed with various Gantrez AN 169solutions (15%, 20%, and 25% w/w GAN solutions in water) together withglycerin, to yield the wet adhesive compositions described in Table 2.The percentage of non-volatile solids in these formulations was greaterthan 50% by weight.

The adhesives were cast on glass slides and were dried at 100° C. for 1hour to yield transparent yellow films (solid compositions are given inTable 3). A first set of the coated glass specimens was qualitativelyevaluated for pressure-sensitive tack (under ambient conditions) bytouching the samples with a nitrile glove, and then by gauging therelative force of resistance required to pull the glove away.Qualitative tack results are given in Table 4. A second set of thecoated glass specimens were pressed together by hand with paper coupons,and were allowed to set for approximately 18 hours before beingsubjected to qualitative peel delamination testing. The paper couponswere then partially peeled from the glass to evaluate relative peelcharacteristics. The samples were then re-adhered by hand, and weresubjected to second peel tests. The results in Table 5 describe thesamples after being subjected to the peel tests. All of the adhesiveswere observed to bond paper to glass.

After the peel tests were complete, three of the adhesives (JM1077-16,JM1077-13, and JM1077-10) were observed to completely delaminate fromthe glass, and the adhesive films remained adhered to the paper. Thesespecimens were separately pressed against corrugated cardboard couponsto yield paper-to-adhesive-to-cardboard laminates. The laminates werethen allowed to set for approximately 18 hours and were subsequentlypeeled apart. The adhesives were qualitatively observed to form strongbonds with the substrates.

TABLE 2 WET COMPOSITIONS OF PLASTICIZED HIGH-SOLIDS WATER- SOLUBLEPROTEIN-CONTAINING ADHESIVES Weight Percent Weight Protein Percent Ratioof Weight Water- Weight Meal Weight GAN Protein/ Percent Based Counter-Percent Extract + Percent Anhydride GAN Non- Sample Extract ion WaterBase Glycerin Polymer Anhydride volatiles No. Type Type (%) (%) (%) (%)(w/w) (%) JM1077-10 JM1072-1 Ca²⁺ 45.67 18.90 30.71 4.72 4.00 54.33JM1077-11 JM1072-1 Ca²⁺ 49.83 38.33 8.01 3.83 10.00 50.17 JM1077-12JM1072-1 Ca²⁺ 48.78 29.27 17.07 4.88 6.00 51.22 JM1077-13 JM1074-5Ca²⁺/Na⁺ 45.67 18.90 30.71 4.72 4.00 54.33 JM1077-14 JM1074-5 Ca²⁺/Na⁺49.83 38.33 8.01 3.83 10.00 50.17 JM1077-15 JM1074-5 Ca²⁺/Na⁺ 48.7829.27 17.07 4.88 6.00 51.22 JM1077-16 JM1074-4 None 45.67 18.90 30.714.72 4.00 54.33 JM1077-17 JM1074-4 None 49.83 38.33 8.01 3.83 10.0050.17 JM1077-18 JM1074-4 None 48.78 29.27 17.07 4.88 6.00 51.22

TABLE 3 DRY COMPOSITIONS OF PLASTICIZED WATER-SOLUBLE PROTEIN-CONTAINING ADHESIVES Weight Weight Percent Weight Percent GAN Ratio ofPhr Glycerin Protein Meal Percent Anhydride Protein/GAN (parts perExtract + base Glycerin Polymer Anhydride Sample No. hundred resin) (%)(%) (%) (w/w) JM1077-10 130.0 34.78 56.52 8.70 4.00 JM1077-11 19.0 76.3915.97 7.64 10.00 JM1077-12 50.0 57.14 33.33 9.52 6.00 JM1077-13 130.034.78 56.52 8.70 4.00 JM1077-14 19.0 76.39 15.97 7.64 10.00 JM1077-1550.0 57.14 33.33 9.52 6.00 JM1077-16 130.0 34.78 56.52 8.70 4.00JM1077-17 19.0 76.39 15.97 7.64 10.00 JM1077-18 50.0 57.14 33.33 9.526.00

TABLE 4 QUALITATIVE PRESSURE-SENSITIVE TACK CHARACTERISTICS OF DRYCOMPOSITIONS OF PLASTICIZED WATER-SOLUBLE PROTEIN-CONTAINING ADHESIVESPhr Tack Characteristics for Glycerin Particular Sample Nos. Ratio of(parts per (Arranged from Lowest Protein/GAN Qualitative Relativehundred Tack to Highest Anhydride Tack resin) Tack in Series) (w/w)Lowest tack samples 19 JM1077-14 < JM1077- 10.0 11 < JM1077-17Intermediate tack 50 JM1077-12 = JM1077- 6.0 samples 15 = JM1077-18 Hightack samples 130 JM1077-16 < JM1077- 4.0 13 < JM1077-10

TABLE 5 QUALITATIVE CHARACTERISTICS OF PAPER-TO-GLASS PEEL SPECIMENSAFTER PEEL TESTING. Phr Glass-to- Glycerin Adhesive Paper Tack of (partsper Sample Color/ Degree of Cohesive Exposed Re-adhesion hundred No.Clarity Delamination Failure Adhesive After Peel resin) JM1077-10Transparent/ Complete peel none high reversible 130.0 yellowdelamination JM1077-11 Transparent/ Remained Partial tear; Low (due toLow (due to 19.0 yellow adhered paper fibers paper fibers on paperfibers) near adhesive surface) surface JM1077-12 Transparent/ RemainedHigh tear; Low (due to Low (due to 50.0 yellow adhered paper fiberspaper fibers on paper fibers) near adhesive surface) surface JM1077-13Transparent/ Complete peel none high reversible 130.0 yellowdelamination JM1077-14 Transparent/ Remained High tear; Low (due to Low(due to 19.0 yellow adhered paper fibers paper fibers on paper fibers)near adhesive surface) surface JM1077-15 Transparent/ Partial Partialtear; Low (due to Low (due to 50.0 yellow delamination paper fiberspaper fibers on paper fibers) from glass near adhesive surface) surfaceJM1077-16 Transparent/ Complete peel none high reversible 130.0 yellowdelamination JM1077-17 Transparent/ Remained High tear; Low (due to Low(due to 19.0 yellow adhered paper fibers paper fibers on paper fibers)near adhesive surface) surface JM1077-18 Transparent/ Partial Partialtear; Low (due to Low (due to 50.0 yellow delamination paper fiberspaper fibers on paper fibers) from glass near adhesive surface) surface

The results demonstrate that the identity and quantity of components inthe adhesive composition may be selected in order to achieve aparticular adhesive response (e.g., a composition having low tack, hightack, low paper tear, or high paper tear, etc.). Features of theadhesive composition that are understood to be important for impactingthe adhesive response include, for example, (1) the ratio of protein toGAN (e.g., 10/1, 6/1, and 4/1); (2) the phr of plasticizer (e.g., 19 to130 phr); and (3) the counter-ion of the base when present (e.g., nocounterion, Na⁺, Ca²⁺, and mixtures of Na⁺ with Ca²⁺). Moreover, theresults demonstrates wet compositions containing greater than 50%non-volatile solids can be used to produce compositions with a range ofadhesive responses.

It is contemplated that the above adhesive compositions can be modifiedto include, for example, additives described in the detailed descriptionabove, such as one or more latex polymers and/or tackifiers. Inaddition, a carboxylic acid containing polymer or a carboxylate saltcontaining polymer may be used in addition to GAN, or in lieu of GAN.Also, the sodium or calcium cations may be replaced with other metalions, such as K⁺, Mg²⁺, Zn²⁺, and Fe²⁺.

Example 10: Preparation of Pressure-Sensitive Adhesives fromWater-Soluble Protein Fraction and Sodium Alginate

High-solids pressure-sensitive adhesives were prepared with a sodiumalginate polymer obtained from Sigma-Aldrich, Inc. (CAS No. 9005-38-3)reacted together with a water-soluble protein fraction obtained fromcanola meal. The water-soluble protein fraction in this example wasisolated and spray-dried by CanPro Ingredients, Ltd., Arborfield,Saskatchewan, Canada. The CanPro water-soluble protein fraction wasmixed with water in the presence and absence of base (1-molal Ca(OH)₂with and without NaOH) to yield the 50% solids (w/w) solution mixturesdescribed in Table 1. A separate solution was prepared containing urea.

TABLE 1 50% (W/W) SOLIDS WATER-SOLUBLE PROTEIN FRACTIONS Weight PercentCanPro Water- Soluble Protein pH After Sample No. Liquid CarrierFraction (%) Mixing JM1072-1 1-molal aqueous Ca(OH)₂ 50 6.14 JM1074-5JM1072-1 [1-molal 50 7.6 aqueous Ca(OH)₂) + 1-molal NaOH solution]JM1074-4 water 50 6.10 JM-1086-1 10% Urea solution 50 6.14

Samples from Table 1 were mixed with various sodium alginate solutions(10% and 15% w/w) together with glycerin, to yield the wet adhesivecompositions described in Table 2. The percentage of non-volatile solidsin these formulations was greater than 52% by weight.

The adhesives were cast on glass slides and were dried at 100° C. for 1hour to yield transparent yellow films (solid compositions are given inTable 3). A first set of coated glass specimens was qualitativelyevaluated for pressure-sensitive tack (under ambient conditions) bytouching the samples with a nitrile glove, and then by gauging therelative force of resistance required to pull the glove away.Qualitative tack results are given in Table 4. A second set of coatedglass specimens were pressed together by hand with paper coupons, andwere allowed to set for approximately 18 hours before being subjected toqualitative peel delamination testing. The paper coupons were thenpartially peeled from the glass to evaluate relative peelcharacteristics. The samples were then re-adhered by hand, and weresubjected to second peel tests.

The results in Table 5 describe the samples after being subjected to thepeel tests. All of the adhesives were observed to bond paper to glass.

TABLE 2 WET COMPOSITIONS OF PLASTICIZED HIGH-SOLIDS WATER- SOLUBLEPROTEIN-CONTAINING ADHESIVES Weight Percent Weight Protein PercentWeight Water- Counter- Weight Meal Weight Na- Ratio of Percent Based ionPercent Extract + Percent Alginate Protein/ Non- Sample Extract TypeWater Base Glycerin Polymer Na-Alginate volatiles No. Type Base (%) (%)(%) (%) (w/w) (%) JM1083-1 JM-1072-1 Ca²⁺ 45.81 19.09 30.39 4.72 4.0554.19 JM-1083-2 JM-1074-5 Ca²⁺/Na⁺ 45.50 18.85 30.95 4.70 4.01 54.50JM-1083-3 JM-1074-4 None 45.51 18.89 30.90 4.70 4.02 54.49 JM-1086-2JM-1086-1 Urea 47.27 18.88 30.71 3.15 5.99 52.74 JM-1086-3 JM-1086-1Urea 45.69 18.84 30.74 4.74 3.98 54.31

TABLE 3 DRY COMPOSITIONS OF PLASTICIZED WATER-SOLUBLE PROTEIN-CONTAINING ADHESIVES Weight Percent Weight Weight Percent Ratio of PhrGlycerin Protein Meal Percent Na-Alginate Protein/Na- (parts perExtract + base Glycerin Polymer Alginate Sample No. hundred resin) (%)(%) (%) (w/w) JM-1083-1 127.7 35.22 56.08 8.70 4.05 JM-1083-2 131.434.58 56.78 8.63 4.01 JM-1083-3 131.0 34.67 56.71 8.62 4.02 JM-1086-2139.4 35.80 58.22 5.98 5.99 JM-1086-3 130.4 34.68 56.59 8.72 3.98

TABLE 4 QUALITATIVE PRESSURE-SENSITIVE TACK CHARACTERISTICS OF DRYCOMPOSITIONS OF PLASTICIZED WATER-SOLUBLE PROTEIN-CONTAINING ADHESIVESTack Characteristics for Particular Sample Weight Ratio of QualitativeRelative Nos. (Arranged from Lowest Protein to Na- Tack Tack to HighestTack in Series) Alginate Highest relative tack 1083-1 = 1083-2 = 1083-3~4 group; all similar to one another Lower relative tack 1086-3 < 1086-2< 1083-1 = ~6 group 1083-2 = 1083-3

TABLE 5 QUALITATIVE CHARACTERISTICS OF PAPER-TO-GLASS PEEL SPECIMENSAFTER PEEL TESTING Phr Glass-to- Glycerin Adhesive Paper Tack of (partsper Sample Color/ Degree of Cohesive Exposed Re-adhesion hundred No.Clarity Delamination Failure Adhesive After Peel resin) JM-1083-1Transparent/ Remained Partial tear; Low (due to Low (due to 127.7Yellow- adhered paper fibers paper fibers paper fibers) Brown nearadhesive on surface) surface JM-1083-2 Transparent/ Remained Partialtear; Low (due to Low (due to 131.4 Yellow- adhered paper fibers paperfibers paper fibers) Brown near adhesive on surface) surface JM-1083-3Transparent/ Remained Partial tear; Low (due to Low (due to 131.0Yellow- adhered paper fibers paper fibers paper fibers) Brown nearadhesive on surface) surface JM-1086-2 Transparent/ Remained Partialtear; Low (due to Low (due to 139.4 Yellow- adhered paper fibers paperfibers paper fibers) Brown near adhesive on surface) surface JM-1086-3Transparent/ Remained Partial tear; Low (due to Low (due to 130.4Yellow- adhered paper fibers paper fibers paper fibers) Brown nearadhesive on surface) surface

The results demonstrate that combinations of a carboxylate-saltfunctionalized polymer and water-soluble protein fraction can be used toproduce a composition having adhesive tack. In addition, this exampledemonstrates that urea may be used to modulate the pH of thecomposition.

Example 11: Preparation of Pressure-Sensitive Adhesives fromWater-Soluble Protein Fraction and Anhydride-Functionalized Copolymerwith a Latex Polymer

High-solids pressure-sensitive adhesives were prepared with an EVA latex(a carboxylated vinyl acetate-ethylene terpolymer stabilized withpoly-(vinyl alcohol), commercially known as VINNAPAS 426® from WackerChemical Corp.; 63% solids by weight and formerly known as AIRFLEX 426®from Air Products, Inc.) and an anhydride-functionalized copolymerreacted together with a water-soluble protein fraction obtained fromcanola meal. The water-soluble protein fraction in this example wasisolated and spray-dried by CanPro Ingredients, Ltd., Arborfield,Saskatchewan, Canada. The CanPro water-soluble protein fraction wasmixed with water in the presence and absence of base (1-molal Ca(OH)₂with and without NaOH) to yield the 50% solids (w/w) solution mixturesdescribed in Table 1. A separate solution was prepared with urea.

TABLE 1 50% (W/W) SOLIDS WATER-SOLUBLE PROTEIN FRACTIONS Weight PercentCanPro Water- Soluble Protein pH After Sample No. Liquid CarrierFraction (%) Mixing JM1072-1 1-molal aqueous 50% 6.14 Ca(OH)₂ JM1074-5JM1072-1 (1-molal 50% 7.6 aqueous Ca(OH)₂) + 1-molal NaOH solutionJM1074-4 water 50% 6.10 JM-1086-1 10% Urea solution 50% 6.14

Samples from Table-1 were mixed with a Gantrez AN 169 solution (15% w/wGAN in water) together with glycerin and a carboxylic acidfunctionalized EVA terpolymer latex (Vinnapas 426) to yield the wetadhesive compositions described in Table 2. The percentage ofnon-volatile solids in these formulations was greater than 50% byweight.

The adhesives were cast on glass slides and were dried at 100° C. for 1hour to yield transparent yellow films (solid compositions are given inTable 3). A first set of coated glass specimens was qualitativelyevaluated for pressure-sensitive tack (under ambient conditions) bytouching the samples with a nitrile glove, and then by gauging therelative force of resistance required to pull the glove away.Qualitative tack results are given in Table 4. A second set of coatedglass specimens were pressed together by hand with paper coupons, andwere allowed to set for approximately 18 hours before being subjected toqualitative peel delamination testing. The paper coupons were thenpartially peeled from the glass to evaluate relative peelcharacteristics. The samples were then re-adhered by hand, and weresubjected to second peel tests.

The results in Table 5 describe the samples after being subjected to thepeel tests. All of the adhesives were observed to bond paper to glass.

TABLE 2 WET COMPOSITIONS OF PLASTICIZED HIGH-SOLIDS WATER- SOLUBLEPROTEIN-CONTAINING ADHESIVES WITH EVA LATEX* Weight Weight Ratio ofSample Percent Percent Protein/ No. Protein Weight EVA Ratio of (GANWeight (Water- Counter- Meal Percent Latex Protein/ Anhydride + PercentBased ion Extract + GAN (solids GAN EVA- Non- Extract Type BaseAnhydride basis Anhydride acid) volatiles Type) Base (%) (%) %) (w/w)(w/w) (%) TP36-1 none 23.32 2.91 13.12 8.00 1.45 52.46 (JM1074-4) TP36-2Ca²⁺ 23.32 2.91 13.12 8.00 1.45 52.46 (JM1072-1) TP36-3 Ca²⁺/Na⁺ 23.322.91 13.12 8.00 1.45 52.46 (JM1074-5) TP36-4 Urea 23.32 2.91 13.12 8.001.45 52.46 (JM1086-1) *All samples contained (i) 13.11% glycerin byweight, and (ii) 47.54 % water by weight.

TABLE 3 DRY COMPOSITIONS OF PLASTICIZED WATER-SOLUBLE PROTEIN-CONTAINING ADHESIVES WITH EVA LATEX Weight Ratio of Percent Protein/ PhrProtein Weight Ratio of (GAN Glycerin Meal Weight Percent WeightProtein/ Anhydride + (parts per Extract + Percent GAN Percent GAN EVA-Sample hundred Base Glycerin Anhydride EVA Anhydride acid) No. resin)(%) (%) (%) (%) (w/w) (w/w) TP36-1 33.3 44.45% 25.00% 5.55% 25.00% 8.001.45 TP36-2 33.3 44.45% 25.00% 5.55% 25.00% 8.00 1.45 TP36-3 33.3 44.45%25.00% 5.56% 25.00% 8.00 1.45 TP36-4 33.3 44.45% 25.00% 5.56% 25.00%8.00 1.45

TABLE 4 QUALITATIVE PRESSURE-SENSITIVE TACK CHARACTERISTICS OF DRYCOMPOSITIONS OF PLASTICIZED WATER-SOLUBLE PROTEIN- CONTAINING ADHESIVESWITH EVA LATEX Tack Characteristics for Weight Ratio of ParticularSample Nos. Weight Ratio of Protein to Phr Glycerin (Arranged fromLowest Protein to (GAN Qualitative Relative (parts per Tack to HighestTack in GAN Anhydride + Tack hundred resin) Series) Anhydride EVA-acid)All samples were 33.3 TP36-1 = TP36-2 = TP36- 8.00 1.45 similar to oneanother; 3 = TP36-4 relative tack was similar to Intermediate tacksamples in Table 4 of Example 9

TABLE 5 QUALITATIVE CHARACTERISTICS OF PAPER-TO-GLASS PEEL SPECIMENSAFTER PEEL TESTING Glass-to- Adhesive Paper Tack of Phr Glycerin SampleColor/ Degree of Cohesive Exposed Re-adhesion (parts per No. ClarityDelamination Failure Adhesive After Peel hundred resin) TP36-1Transparent/ Remained High tear; Low (due to Low (due to 33.3 yellowadhered paper fibers paper fibers on paper fibers) near adhesivesurface) surface TP36-2 Transparent/ Remained High tear; Low (due to Low(due to 33.3 yellow adhered paper fibers paper fibers on paper fibers)near adhesive surface) surface TP36-3 Transparent/ Remained High tear;Low (due to Low (due to 33.3 yellow adhered paper fibers paper fibers onpaper fibers) near adhesive surface) surface TP36-4 Transparent/Remained High tear; Low (due to Low (due to 33.3 yellow adhered paperfibers paper fibers on paper fibers) near adhesive surface) surface

The results demonstrate that combinations of an anhydride compound,carboxylic acid functionalized polymer, and water-soluble proteinfraction can be used to produce a composition having adhesive tack. Thecarboxylic acid functionalized polymer (VINNAPAS 426® (formerlyAirFlex-426 from Wacker Chemical Corp)) was provided in the form of alatex. It is understood that the adhesive tack of the composition can bemodulated by selecting a latex polymer having a different Tg, using amixture of latex polymers having different Tg values, and/or adjustingthe amount of plasticizer and/or tackifier in the composition.

Example 12: Bleed Test Analysis of Adhesive Formulations

The adhesive formulations as described in Tables 2 and 3 from Example 11(TP36-1, TP36-2, TP36-3 and TP36-4) were cast as thin films on glassmicroscope slides using a metal spatula to spread the adhesive on oneside of the glass. The coated slides were placed in an oven and dried at100° C. for 1 hour to yield transparent, yellow, tacky films. Two setsof glass slides were prepared for each adhesive sample.

Using a Hewlett Packard, HP Photosmart 3100 series printer, the phase“BLEED TEST” was printed on Staples Multipurpose 22 lb. (83 g/m³), 98Brightness paper. The phrase “BLEED TEST” was printed three times: oncein black font, once in red font, and once in blue font. The HPPhotosmart 3100 series uses ink cartridge numbers HP 92 (black) and HP93 (color). When printed on paper, these inks are susceptible torunning, smearing and bleeding into the paper when they come intocontact with liquids (e.g., water, glycerin, oils, etc.). These inks arealso susceptible to bleeding from contact with adhesive formulations,particularly when the formulation ingredients are capable of migratingthrough the paper.

The paper specimens were cut into 2-cm×6-cm coupons, and were printedwith the phase “BLEED TEST” in three separate colors (i.e., black, red,and blue as described above). The coupons were then pressed by hand ontothe pre-dried, adhesive-coated glass slides, as illustrated in FIG. 23(where the left-most recitation of “BLEED TEST” on each coupon wasprinted using black ink, the middle recitation of “BLEED TEST” on eachcoupon was printed using red ink, and the right-most recitation of“BLEED TEST” on each coupon was printed using blue ink). The two sets ofsamples were then placed in a 100° C. oven. One set of samples wasremoved from the oven after 1 hour, and the samples were examined forpossible penetration of the adhesive through the paper (as judged byoff-white discoloration), and for any signs of smearing or distortion ofthe printed ink. None of the 1-hour samples showed any signs of adhesivepenetration into the paper or blurring/bleeding of the printed words.

The second set of samples remained in the oven for 16 hours. Uponremoval from the oven, the 16-hour samples were also examined forpossible penetration of the adhesive through the paper and for anysmearing or distortion of the printed inks. Like the 1-hour samples, the16-hour samples showed no signs of adhesive penetration into the paperor blurring/bleeding of the printed words.

All samples were placed on a bench top, and were allowed to remain therefor 7 days under ambient laboratory conditions. After 7 days, thesamples were re-examined. Sample TP36-4 showed evidence of adhesivepenetration through the paper and the printed words were observed tobleed. Sample TP36-1 also showed signs of adhesive penetration but notas much as TP36-4. By contrast, samples TP36-2 and TP36-3 showed no signof adhesive penetration into the paper or blurring/bleeding of theprinted words.

The samples were then allowed to remain on the bench-top under ambientlaboratory conditions for 21 days. The paper coupons on samples TP36-1and TP36-4 remained discolored and the words were observed to bleed andsmear due to continued adhesive penetration through the paper. On theother hand, samples TP 36-2 and TP 36-3 showed no sign of adhesivepenetration into the paper or blurring/bleeding of the printed words.

It is noted that sample TP36-2 contained Ca²⁺ counterions, and sampleTP36-3 contained Ca²⁺ and Na¹⁺ counterions. In contrast, samples TP36-1and TP-36-4 did not have Ca²⁺ counterions or Na¹⁺ counterions. The bleedtest results show that combinations of an anhydride functionalizedcompound, a carboxylic acid functionalized polymer, and a water-solubleprotein fraction can be used to produce an adhesive composition havingboth good adhesive tack characteristics and good bleed resistance,particularly when the adhesive formulation also incorporates acounterion (e.g., Ca²⁺ or Na¹⁺). Such formulations are contemplated foruse in the preparation bleed-resistant printed labels for variousend-use applications. It is further understood from results of thisbleed test that bleed-resistance of the adhesive can be tuned by theselection of components used in the adhesive composition.

Accordingly, experimental results in this Example and other Examplespresented herein collectively demonstrate that it is possible to adjustthe properties of the adhesive composition by selecting particularcomponents for inclusion in the adhesive composition. For instance, asnoted in Example 9, multiple features of the adhesive composition arecapable of impacting the adhesive properties including, for example, (1)the ratio of protein to anhydride-functionalized polymer, (2) the phr ofthe plasticizer; and (3) the counter-ion of the base when present. Asnoted in Example 6, the water-soluble protein fraction was observed topreferentially react with an anhydride copolymer in the presence of abase. In addition, the presence of a counterion from the base (e.g.,Ca²⁺ or Na¹⁺) led to the additional formation of carboxylate salts.Importantly, bidentate counterions such as Ca²⁺ can lead to theformation of interchain crosslinking via ionic bridging betweencarboxylate groups from neighboring polymeric chains. It can beappreciated that these types of reaction products can lead to theformation of adhesive polymers with enhanced properties such asincreased toughness, higher cohesive strength, improved moistureresistance, and improved bleed resistance as demonstrated by the presentexample (the two samples that contained the base counterion exhibitedbetter bleed resistance than analogous samples made without thecounterions). As noted in this Example, the presence of sodium orcalcium can make the adhesive composition more resistant to bleeding.

In an analogous set of experiments, printed paper coupons were alsoadhered to glass slides using the sodium alginate-based adhesives fromExample 10. Most of these adhesive formulations were prepared with basecounterions like those used to prepare the adhesive formulations inExample 11. Like the adhesives from Example 11, none of the sodiumalginate-based samples showed signs of penetration into the paper orblurring/bleeding of the printed words after 1 hour or 16 hours in theoven. By contrast however, when the sodium alginate-based samples wereaged on a bench top for 7 days under ambient laboratory conditions, allof the sodium alginate samples from Example 10 showed penetration of theadhesive through the paper. This was manifested as a darkening of thepaper accompanied by a blurring/bleeding of the ink.

Thus, the use of a counterion with a carboxylate functionalized polymeris not necessarily sufficient to impart bleed resistance. Instead, it isalso important to consider the other formulation ingredients that areused in combination with the water-soluble protein fraction. As shown inthis comparative example, an anhydride copolymer with a carboxylated EVAlatex polymer is favored over the use of sodium alginate polymer alone.

INCORPORATION BY REFERENCE

The entire disclosure of each of the patent and scientific documentsreferred to herein is incorporated by reference for all purposes.

EQUIVALENTS

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The foregoingembodiments are therefore to be considered in all respects illustrativerather than limiting on the invention described herein. Scope of theinvention is thus indicated by the appended claims rather than by theforegoing description, and all changes that come within the meaning andrange of equivalency of the claims are intended to be embraced therein.

We claim:
 1. An adhesive composition comprising: (a) an isolatedwater-soluble protein fraction; and (b) at least 0.1% (w/w) of aprotein-bonding agent that is an anhydride compound selected from thegroup consisting of poly(alkylvinylether-co-unsaturated anhydride),polyalkylene-unsaturated anhydride copolymer, arylalkene-unsaturatedanhydride copolymer, and combinations thereof.
 2. The composition ofclaim 1, wherein the isolated water-soluble protein fraction comprisesone or more of the following features: i. an amide-I absorption bandbetween about 1633 cm⁻¹ and 1680 cm⁻¹, as determined by solid stateFTIR; ii. an amide-II band between approximately 1522 cm⁻¹ and 1560cm⁻¹, as determined by solid state FTIR; iii. two prominent 1° amide N—Hstretch absorption bands centered at about 3200 cm⁻¹, and at about 3300cm⁻¹, as determined by solid state FTIR; iv. a prominent cluster ofprotonated nitrogen nuclei defined by ¹⁵N chemical shift boundaries atabout 94 ppm and at about 100 ppm, and ¹H chemical shift boundaries atabout 7.6 ppm and at about 8.1 ppm, as determined by solution state,two-dimensional proton-nitrogen coupled NMR; v. an average molecularweight of between about 600 and about 2,500 Daltons; or vi. an inabilityto stabilize an oil-in-water emulsion, wherein, when an aqueous solutioncomprising 14 parts by weight of protein dissolved or dispersed in 86parts by weight of water is admixed with 14 parts by weight of PMDI, theaqueous solution and the PMDI produce an unstable suspension thatmacroscopically phase separates under static conditions within fiveminutes after mixing.
 3. The composition of claim 1, wherein theisolated water-soluble protein fraction is derived from corn, wheat,sunflower, cotton, rapeseed, canola, castor, soy, camelina, flax,jatropha, mallow, peanuts, algae, sugarcane begasse, tobacco, whey, or acombination thereof.
 4. The composition of claim 3, wherein the ratio of(i) the weight percent of isolated water-soluble protein fraction in theadhesive composition to (ii) the weight percent of protein-bonding agentin the adhesive composition is from about 8:1 to about 1:1.
 5. Thecomposition of claim 3, wherein the composition comprises from about 5%(w/w) to about 50% (w/w) isolated water-soluble protein fraction.
 6. Thecomposition of claim 3, wherein the composition comprises from about 2%(w/w) to about 5% (w/w) isolated water-soluble protein fraction.
 7. Anadhesive composition comprising: (a) ground plant meal; and (b) at least0.1% (w/w) of a protein-bonding agent that is an anhydride compoundselected from the group consisting ofpoly(alkylvinylether-co-unsaturated anhydride), polyalkylene-unsaturatedanhydride copolymer, arylalkene-unsaturated anhydride copolymer, andcombinations thereof.
 8. The composition of claim 1, wherein thecomposition comprises from 0.1% (w/w) to about 20% (w/w) protein-bondingagent.
 9. The composition of claim 1, wherein the composition comprisesfrom 0.1% (w/w) to about 1.5% (w/w) protein-bonding agent.
 10. Thecomposition of claim 1, wherein the anhydride compound is apoly(alkylvinylether-co-unsaturated anhydride) orpolyalkylene-unsaturated anhydride copolymer.
 11. The composition ofclaim 7, wherein the anhydride compound is apoly(alkylvinylether-co-unsaturated anhydride) orpolyalkylene-unsaturated anhydride copolymer.
 12. The composition ofclaim 1, wherein the anhydride compound ispoly(methylvinylether-co-maleic anhydride), polypropylene-maleicanhydride copolymer, polyethylene-maleic anhydride copolymer, orstyrene-maleic anhydride copolymer.
 13. The composition of claim 1,wherein the anhydride compound is a poly(methylvinylether-co-maleicanhydride).
 14. The composition of claim 1, wherein the anhydridecompound is a partially hydrolyzed poly(methylvinylether-co-maleicanhydride).
 15. The composition of claim 1, wherein the anhydridecompound is a polymer comprising: (a) at least one

or a salt thereof, wherein x is independently for each occurrence aninteger from 1 to 10, y is independently for each occurrence an integerof from 1 to 10, and z is independently for each occurrence an integerof from 1 to 10; and (b) at least one

wherein a is independently for each occurrence an integer from 1 to 10,b is independently for each occurrence an integer of from 1 to 10, and cis independently for each occurrence an integer of from 1 to
 10. 16. Thecomposition of claim 1, wherein the composition is in the form of aliquid.
 17. The composition of claim 1, further comprising water. 18.The composition of claim 17, wherein the water is present in an amountof from about 40% w/w to about 60% w/w of the adhesive composition. 19.The composition of claim 17, wherein the water is present in an amountof from about 80% w/w to about 90% w/w of the adhesive composition. 20.The composition of claim 1, further comprising a plasticizer.
 21. Thecomposition of claim 20, wherein the composition comprises from about 5%(w/w) to about 30% (w/w) of a plasticizer.
 22. The composition of claim20, wherein the plasticizer is a polyol.
 23. The composition of claim20, wherein the plasticizer is glycerol, sorbitol, glycerol diacetate,ethylphthalyl glycolate, butylphthalylethyl glycolate, butylglycolate,propylene glycol, polyethylene glycol, polyethylene glycol sorbitanmonooleate, sorbitan monooleate, 1,2-propane diol, or 1,3-propane diol.24. The composition of claim 20, wherein the plasticizer is glycerol.25. The composition of claim 1, wherein the composition is in the formof an aqueous dispersion.
 26. The composition of claim 1, wherein thecomposition comprises at least 10% (w/w) non-volatile solid material.27. A solid binder composition formed by curing a composition ofclaim
 1. 28. The solid binder composition of claim 27, wherein the solidbinder composition is tacky at least over a temperature range of about10° C. to about 30° C.
 29. The solid binder composition of claim 27,wherein the solid binder composition has one or more of the followingfeatures: (a) comprises from about 10% to about 40% (w/w) isolatedwater-soluble protein fraction; (b) comprises from about 10% to about80% (w/w) plasticizer; (c) comprises from about 2% to about 25% (w/w)protein-bonding agent; (d) the ratio of (i) the weight percent ofisolated water-soluble protein fraction in the adhesive composition to(ii) the weight percent of protein-bonding agent in the adhesivecomposition is from about 10:1 to about 1:1; and (e) is tacky at leastover a temperature range of about 20° C. to about 30° C.
 30. A method ofbonding a first article to a second article comprising: (a) depositingon a surface of the first article the adhesive composition of claim 1thereby to create a binding area; and (b) contacting the binding surfacewith a surface of the second article thereby to bond the first articleto the second article.
 31. A method of producing a composite materialcomprising: (a) combining a first article and a second article with theadhesive composition of claim 1 to produce a mixture; and (b) curing themixture produced by step (a) to produce the composite material.
 32. Themethod of claim 30, wherein the first article, the second article orboth the first and second articles are lignocellulosic materials, orcomposite materials containing lignocellulosic material.
 33. An articleproduced using the adhesive composition of claim
 1. 34. An articlecomprising two or more components bonded together using the adhesivecomposition of claim
 1. 35. The article of claim 34, wherein the bondedcomponents are selected from the group consisting of paper, wood, glass,metal, fiberglass, wood fiber, ceramic, ceramic powder, plastic, and acombination thereof.
 36. The composition of claim 7, wherein the groundplant meal is derived from corn, wheat, sunflower, cotton, rapeseed,canola, castor, soy, camelina, flax, jatropha, mallow, peanuts, algae,sugarcane bagasse, tobacco, whey, or a combination thereof.
 37. Thecomposition of claim 7, wherein the composition comprises from about 2%(w/w) to about 25% (w/w) ground plant meal.
 38. The composition of claim7, wherein the ratio of (i) the weight percent of ground plant meal inthe adhesive composition to (ii) the weight percent of protein-bondingagent in the adhesive composition is from about 10:1 to about 1:1. 39.The composition of claim 7, wherein the composition comprises from 0.1%(w/w) to about 20% (w/w) protein-bonding agent.
 40. The composition ofclaim 7, further comprising water.
 41. The composition of claim 40,wherein the adhesive composition has a pH in the range of from about 7to about
 10. 42. The composition of claim 17, wherein the adhesivecomposition has a pH in the range of from about 7 to about
 10. 43. Anarticle comprising two or more components bonded together using theadhesive composition of claim 7.